Washington (CNN) With nearly all of the expected 2016 presidential candidates formally in the race, a new CNN/ORC national poll finds two recent entrants to the GOP field on the rise, while Hillary Clinton maintains her position atop the Democratic field, though holding a slightly slimmer lead.

Former Florida Gov. Jeb Bush and businessman Donald Trump top the list of GOP presidential contenders following their back-to-back campaign launches in mid-June, and are the only two Republican candidates holding double-digit support among Republicans and Republican-leaning independents.

For his part, Trump specifically responded to the poll results Wednesday afternoon saying the numbers are "representative of the response we are receiving from all over the country."

"I am committed to addressing the issues our country is facing and am confident my business mindset and common sense solutions are resonating with the American people," Trump said in a statement Wednesday afternoon. "Politicians are all talk and no action and the American public is ready for a leader with a proven track record of success."

Clinton, though, continues to lead all GOP candidates in head-to-head general election match-ups.

Republicans

Bush stands at 19%, up from 13% in May -- and his best showing in CNN/ORC polling since December. Trump follows at 12%, up from 3% before his announcement. Former Arkansas Gov. Mike Huckabee (8%), neurosurgeon Ben Carson (7%) and Kentucky Sen. Rand Paul (7%) round out the top five.

Notably absent from this top five -- though statistically speaking not far behind -- are Florida Sen. Marco Rubio (6%, down from 14% in May) and Wisconsin Gov. Scott Walker (6%, down slightly from 10%). Both had been top five candidates in each of the last two CNN/ORC polls, and Walker had been in the top five since February.

The poll, conducted just before New Jersey Gov. Chris Christie formally launched his campaign with a rally in Livingston, New Jersey, on Tuesday, also finds that Christie begins his push for the presidency with just 3% support.

The findings suggest Bush is making progress toward being seen as the frontrunner in a field that has long lacked a clear leader. He holds a significant lead over the second-place candidate Trump, is seen as the candidate who could best handle illegal immigration and social issues, and runs about even with Trump and well ahead of the other candidates when Republicans are asked which candidate can best handle the economy.

Photos: Potential 2016 presidential candidates Former Florida Gov. Jeb Bush has said his decision to run for the Republican nomination will be based on two things: his family and whether he can lift America's spirit. His father and brother are former Presidents. Hide Caption 1 of 19 Photos: Potential 2016 presidential candidates Wisconsin Gov. Scott Walker has created a political committee that will help him travel and raise money while he considers a 2016 bid. Additionally, billionaire businessman David Koch said in a private gathering in Manhattan this month that he wants Walker to be the next president, but he doesn't plan to back anyone in the primaries. Hide Caption 2 of 19 Photos: Potential 2016 presidential candidates Louisiana Gov. Bobby Jindal is establishing a committee to formally explore a White House bid. "If I run, my candidacy will be based on the idea that the American people are ready to try a dramatically different direction," he said in a news release provided to CNN on Monday, May 18 Hide Caption 3 of 19 Photos: Potential 2016 presidential candidates Sen. Bernie Sanders , an independent from Vermont who caucuses with Democrats, has said the United States needs a "political revolution" of working-class Americans looking to take back control of the government from billionaires. He first announced the run in an email to supporters early on the morning of Thursday, April 30. Hide Caption 4 of 19 Photos: Potential 2016 presidential candidates On March 2, retired neurosurgeon Ben Carson announced the launch of an exploratory committee. The move will allow him to raise money that could eventually be transferred to an official presidential campaign and indicates he is on track with stated plans to formally announce a bid in May. Hide Caption 5 of 19 Photos: Potential 2016 presidential candidates South Carolina Sen. Lindsey Graham has said he'll make a decision about a presidential run sometime soon. A potential bid could focus on Graham's foreign policy stance. Hide Caption 6 of 19 Photos: Potential 2016 presidential candidates Hillary Clinton launched her presidential bid Sunday, April 12, through a video message on social media. She continues to be considered the overwhelming front-runner among possible 2016 Democratic presidential candidates. Hide Caption 7 of 19 Photos: Potential 2016 presidential candidates Sen. Marco Rubio announced his bid for the 2016 presidency on Monday, April 13, a day after Hillary Clinton, with a rally in Florida. He's a Republican rising star from Florida who swept into office in 2010 on the back of tea party fervor. But his support of comprehensive immigration reform, which passed the Senate but has stalled in the House, has led some in his party to sour on his prospects. Hide Caption 8 of 19 Photos: Potential 2016 presidential candidates Lincoln Chafee, a Republican-turned-independent-turned-Democrat former governor and senator of Rhode Island, said he's running for president on Thursday, April 16, as a Democrat, but his spokeswoman said the campaign is still in the presidential exploratory committee stages. Hide Caption 9 of 19 Photos: Potential 2016 presidential candidates Jim Webb, the former Democratic senator from Virginia, is entertaining a 2016 presidential run. In January, he told NPR that his party has not focused on white, working-class voters in past elections. Hide Caption 10 of 19 Photos: Potential 2016 presidential candidates Vice President Joe Biden has twice before made unsuccessful bids for the Oval Office -- in 1988 and 2008. A former senator known for his foreign policy and national security expertise, Biden made the rounds on the morning shows recently and said he thinks he'd "make a good President." Hide Caption 11 of 19 Photos: Potential 2016 presidential candidates New Jersey Gov. Chris Christie has started a series of town halls in New Hampshire to test the presidential waters, becoming more comfortable talking about national issues and staking out positions on hot topic debates. Hide Caption 12 of 19 Photos: Potential 2016 presidential candidates Rep. Paul Ryan, a former 2012 vice presidential candidate and fiscally conservative budget hawk, says he's keeping his "options open" for a possible presidential run but is not focused on it. Hide Caption 13 of 19 Photos: Potential 2016 presidential candidates Sen. Rand Paul officially announced his presidential bid on Tuesday, April 7, at a rally in Louisville, Kentucky. The tea party favorite probably will have to address previous controversies that include comments on civil rights, a plagiarism allegation and his assertion that the top NSA official lied to Congress about surveillance. Hide Caption 14 of 19 Photos: Potential 2016 presidential candidates Texas Sen. Ted Cruz announced his 2016 presidential bid on Monday, March 23, in a speech at Liberty University. The first-term Republican and tea party darling is considered a gifted orator and smart politician. He is best known in the Senate for his marathon filibuster over defunding Obamacare. Hide Caption 15 of 19 Photos: Potential 2016 presidential candidates Democrat Martin O'Malley, the former Maryland governor, released a "buzzy" political video in November 2013 in tandem with visits to New Hampshire. He also headlined a Democratic Party event in South Carolina, which holds the first Southern primary. Hide Caption 16 of 19 Photos: Potential 2016 presidential candidates Republican Rick Perry, the former Texas governor, announced in 2013 that he would not be seeking re-election, leading to speculation that he might mount a second White House bid. Hide Caption 17 of 19 Photos: Potential 2016 presidential candidates Former Pennsylvania Sen. Rick Santorum, a social conservative, gave Mitt Romney his toughest challenge in the nomination fight last time out and has made trips recently to early voting states, including Iowa and South Carolina. Hide Caption 18 of 19 Photos: Potential 2016 presidential candidates Political observers expect New York Gov. Andrew Cuomo to yield to Hillary Clinton's run in 2016, fearing there wouldn't be room in the race for two Democrats from the Empire State. Hide Caption 19 of 19

But there are sticking points for Bush. He fares slightly worse across all three issues tested when only registered voters are considered. Registered voters tend to be more conservative and older than Republicans as a whole, and are more apt to actually vote when the primaries come around.

Looking at how each candidate fares among those subgroups, conservatives split their support between Bush and Trump, 12% back each. Likewise, among voters age 50 or older, 14% support Bush and 14% back Trump. By contrast, among Republicans under age 50, Bush is the only candidate in double-digits with 23%, Trump has just 9% support. And moderate or liberal Republicans back Bush over Trump 27% to 10%.

Trump's competitiveness among those older and more conservative Republicans also helps explain Walker's and Rubio's declines. In April, 16% of Republicans age 50 or older backed Rubio, 14% Walker. Now, Rubio has just 6% among this group and Walker has 7%. Trump grew from 2% in May to 14% now.

Among conservatives in May, Rubio led the field with 15%, Walker was just behind at 14%. Bush had 11%, about the same as in the current poll. Now, Walker has fallen to 8%, and Rubio is down five points to 10%. And Trump has grown from 2% to 12%. Rubio also lost ground among moderate or liberal Republicans, just 1% back Rubio in the new poll, down from 11%.

Democrats

On the Democratic side, Hillary Clinton continues to hold all the cards. Nationally, she leads all other candidates by more than 40 points, with 57% of Democrats and Democratic-leaning independents behind her, 16% backing Vice President Joe Biden, 14% Vermont Sen. Bernie Sanders , 2% Jim Webb and 1% or less for former Maryland Gov. Martin O'Malley and former Rhode Island Gov. Lincoln Chafee

The poll holds better news for Biden than it does for Sanders, who has made gains against Clinton in recent polling in Iowa and New Hampshire. But Biden actually tops the list as national Democrats' second-choice candidate, 35% say he's their second pick, compared with 14% who say Sanders is.

Photos: Hillary Clinton's life in the spotlight Hillary Clinton accepts the Democratic Party's nomination for president at the Democratic National Convention in Philadelphia on July 28, 2016. The former first lady, U.S. senator and secretary of state was the first woman to lead the presidential ticket of a major political party. Hide Caption 1 of 43 Photos: Hillary Clinton's life in the spotlight Before marrying Bill Clinton, she was Hillary Rodham. Here she attends Wellesley College in Massachusetts. Her commencement speech at Wellesley's graduation ceremony in 1969 attracted national attention. After graduating, she attended Yale Law School. Hide Caption 2 of 43 Photos: Hillary Clinton's life in the spotlight Rodham was a lawyer on the House Judiciary Committee, whose work led to impeachment charges against President Richard Nixon in 1974. Hide Caption 3 of 43 Photos: Hillary Clinton's life in the spotlight In 1975, Rodham married Bill Clinton, whom she met at Yale Law School. He became the governor of Arkansas in 1978. In 1980, the couple had a daughter, Chelsea. Hide Caption 4 of 43 Photos: Hillary Clinton's life in the spotlight Arkansas' first lady, now using the name Hillary Rodham Clinton, wears her inaugural ball gown in 1985. Hide Caption 5 of 43 Photos: Hillary Clinton's life in the spotlight The Clintons celebrate Bill's inauguration in Little Rock, Arkansas, in 1991. He was governor from 1983 to 1992, when he was elected President. Hide Caption 6 of 43 Photos: Hillary Clinton's life in the spotlight Bill Clinton comforts his wife on the set of "60 Minutes" after a stage light broke loose from the ceiling and knocked her down in January 1992. Hide Caption 7 of 43 Photos: Hillary Clinton's life in the spotlight In June 1992, Clinton uses a sewing machine designed to eliminate back and wrist strain. She had just given a speech at a convention of the International Ladies' Garment Workers Union. Hide Caption 8 of 43 Photos: Hillary Clinton's life in the spotlight During the 1992 presidential campaign, Clinton jokes with her husband's running mate, Al Gore, and Gore's wife, Tipper, aboard a campaign bus. Hide Caption 9 of 43 Photos: Hillary Clinton's life in the spotlight Clinton accompanies her husband as he takes the oath of office in January 1993. Hide Caption 10 of 43 Photos: Hillary Clinton's life in the spotlight The Clintons share a laugh on Capitol Hill in 1993. Hide Caption 11 of 43 Photos: Hillary Clinton's life in the spotlight Clinton unveils the renovated Blue Room of the White House in 1995. Hide Caption 12 of 43 Photos: Hillary Clinton's life in the spotlight Clinton waves to the media in January 1996 as she arrives for an appearance before a grand jury in Washington. The first lady was subpoenaed to testify as a witness in the investigation of the Whitewater land deal in Arkansas. The Clintons' business investment was investigated, but ultimately they were cleared of any wrongdoing. Hide Caption 13 of 43 Photos: Hillary Clinton's life in the spotlight The Clintons hug as Bill is sworn in for a second term as President. Hide Caption 14 of 43 Photos: Hillary Clinton's life in the spotlight The first lady holds up a Grammy Award, which she won for her audiobook "It Takes a Village" in 1997. Hide Caption 15 of 43 Photos: Hillary Clinton's life in the spotlight The Clintons dance on a beach in the U.S. Virgin Islands in January 1998. Later that month, Bill Clinton was accused of having a sexual relationship with former White House intern Monica Lewinsky. Hide Caption 16 of 43 Photos: Hillary Clinton's life in the spotlight Clinton looks on as her husband discusses the Monica Lewinsky scandal in the Roosevelt Room of the White House on January 26, 1998. Clinton declared, "I did not have sexual relations with that woman." In August of that year, Clinton testified before a grand jury and admitted to having "inappropriate intimate contact" with Lewinsky, but he said it did not constitute sexual relations because they had not had intercourse. He was impeached in December on charges of perjury and obstruction of justice. Hide Caption 17 of 43 Photos: Hillary Clinton's life in the spotlight The first family walks with their dog, Buddy, as they leave the White House for a vacation in August 1998. Hide Caption 18 of 43 Photos: Hillary Clinton's life in the spotlight President Clinton makes a statement at the White House in December 1998, thanking members of Congress who voted against his impeachment. The Senate trial ended with an acquittal in February 1999. Hide Caption 19 of 43 Photos: Hillary Clinton's life in the spotlight Clinton announces in February 2000 that she will seek the U.S. Senate seat in New York. She was elected later that year. Hide Caption 20 of 43 Photos: Hillary Clinton's life in the spotlight Clinton makes her first appearance on the Senate Environment and Natural Resources Committee. Hide Caption 21 of 43 Photos: Hillary Clinton's life in the spotlight Sen. Clinton comforts Maren Sarkarat, a woman who lost her husband in the September 11 terrorist attacks, during a ground-zero memorial in October 2001. Hide Caption 22 of 43 Photos: Hillary Clinton's life in the spotlight Clinton holds up her book "Living History" before a signing in Auburn Hills, Michigan, in 2003. Hide Caption 23 of 43 Photos: Hillary Clinton's life in the spotlight Clinton and another presidential hopeful, U.S. Sen. Barack Obama, applaud at the start of a Democratic debate in 2007. Hide Caption 24 of 43 Photos: Hillary Clinton's life in the spotlight Obama and Clinton talk on the plane on their way to a rally in Unity, New Hampshire, in June 2008. She had recently ended her presidential campaign and endorsed Obama. Hide Caption 25 of 43 Photos: Hillary Clinton's life in the spotlight Obama is flanked by Clinton and Vice President-elect Joe Biden at a news conference in Chicago in December 2008. He had designated Clinton to be his secretary of state. Hide Caption 26 of 43 Photos: Hillary Clinton's life in the spotlight Clinton, as secretary of state, greets Russian Prime Minister Vladimir Putin during a meeting just outside Moscow in March 2010. Hide Caption 27 of 43 Photos: Hillary Clinton's life in the spotlight The Clintons pose on the day of Chelsea's wedding to Marc Mezvinsky in July 2010. Hide Caption 28 of 43 Photos: Hillary Clinton's life in the spotlight In this photo provided by the White House, Obama, Clinton, Biden and other members of the national security team receive an update on the mission against Osama bin Laden in May 2011. Hide Caption 29 of 43 Photos: Hillary Clinton's life in the spotlight Clinton checks her Blackberry inside a military plane after leaving Malta in October 2011. In 2015, The New York Times reported that Clinton exclusively used a personal email account during her time as secretary of state. The account, fed through its own server, raises security and preservation concerns. Clinton later said she used a private domain out of "convenience," but admits in retrospect "it would have been better" to use multiple emails. Hide Caption 30 of 43 Photos: Hillary Clinton's life in the spotlight Clinton arrives for a group photo before a forum with the Gulf Cooperation Council in March 2012. The forum was held in Riyadh, Saudi Arabia. Hide Caption 31 of 43 Photos: Hillary Clinton's life in the spotlight Obama and Clinton bow during the transfer-of-remains ceremony marking the return of four Americans, including U.S. Ambassador Christopher Stevens, who were killed in Benghazi, Libya, in September 2012. Hide Caption 32 of 43 Photos: Hillary Clinton's life in the spotlight Clinton ducks after a woman threw a shoe at her while she was delivering remarks at a recycling trade conference in Las Vegas in 2014. Hide Caption 33 of 43 Photos: Hillary Clinton's life in the spotlight Clinton, now running for President again, performs with Jimmy Fallon during a "Tonight Show" skit in September 2015. Hide Caption 34 of 43 Photos: Hillary Clinton's life in the spotlight Clinton testifies about the Benghazi attack during a House committee meeting in October 2015. "I would imagine I have thought more about what happened than all of you put together," she said during the 11-hour hearing. "I have lost more sleep than all of you put together. I have been wracking my brain about what more could have been done or should have been done." Months earlier, Clinton had acknowledged a "systemic breakdown" as cited by an Accountability Review Board, and she said that her department was taking additional steps to increase security at U.S. diplomatic facilities. Hide Caption 35 of 43 Photos: Hillary Clinton's life in the spotlight U.S. Sen. Bernie Sanders shares a lighthearted moment with Clinton during a Democratic presidential debate in October 2015. It came after Sanders gave his take on the Clinton email scandal. "The American people are sick and tired of hearing about the damn emails," Sanders said. "Enough of the emails. Let's talk about the real issues facing the United States of America." Hide Caption 36 of 43 Photos: Hillary Clinton's life in the spotlight Clinton is reflected in a teleprompter during a campaign rally in Alexandria, Virginia, in October 2015. Hide Caption 37 of 43 Photos: Hillary Clinton's life in the spotlight Clinton walks on her stage with her family after winning the New York primary in April. Hide Caption 38 of 43 Photos: Hillary Clinton's life in the spotlight After Clinton became the Democratic Party's presumptive nominee, this photo was posted to her official Twitter account. "To every little girl who dreams big: Yes, you can be anything you want -- even president," Clinton said. "Tonight is for you." Hide Caption 39 of 43 Photos: Hillary Clinton's life in the spotlight Obama hugs Clinton after he gave a speech at the Democratic National Convention in Philadelphia. The president said Clinton was ready to be commander in chief. "For four years, I had a front-row seat to her intelligence, her judgment and her discipline," he said, referring to her stint as his secretary of state. Hide Caption 40 of 43 Photos: Hillary Clinton's life in the spotlight Clinton arrives at a 9/11 commemoration ceremony in New York on September 11. Clinton, who was diagnosed with pneumonia two days before, left early after feeling ill. A video appeared to show her stumble as Secret Service agents helped her into a van. Hide Caption 41 of 43 Photos: Hillary Clinton's life in the spotlight Clinton addresses a campaign rally in Cleveland on November 6, two days before Election Day. She went on to lose Ohio -- and the election -- to her Republican opponent, Donald Trump. Hide Caption 42 of 43 Photos: Hillary Clinton's life in the spotlight After conceding the presidency to Trump in a phone call earlier, Clinton addresses supporters and campaign workers in New York on Wednesday, November 9. Her defeat marked a stunning end to a campaign that appeared poised to make her the first woman elected US president. Hide Caption 43 of 43

While both trail Clinton by wide margins on all four candidate attributes tested, Biden tops Sanders on three of them: as the strongest leader in the field, having the best chance to win, and representing the values of Democrats "like yourself." The two are even in second behind Clinton as the candidate who cares the most about people like you.

The only glimmer of Sanders' early state appeal in this poll comes when Democrats are asked which of the Democratic candidates best represents the values of Democrats like yourself. On that question, among liberal Democrats, Sanders runs about even with Clinton, with 38% saying Clinton best reflects their values and 35% saying Sanders does. Among moderate Democrats, however, Clinton holds a broad edge, 52% say she best represents their values while just 10% say Sanders does.

General election

Looking ahead to the general election, Clinton continues to hold significant leads over Bush (54% Clinton to 41% Bush) and Christie (56% Clinton to 37% Christie). She has also opened up wide leads over Rubio (56% Clinton to 39% Rubio) and Walker (57% Clinton to 38% Walker), as those two have slipped among independents. Clinton's clearest advantage, however, is over Donald Trump, 59% say they would vote for Clinton if the 2016 match-up were between her and Trump, 34% say they would back Trump.

The economy, health care and terrorism remain dominant issues in Americans' minds as the 2016 election gets closer, with 88% calling the economy an extremely or very important issue, 83% rating health care that important and 81% calling terrorism a top issue.

Foreign policy follows, with 71% calling it deeply important, and about 6-in-10 each call illegal immigration (62%) and race relations (61%) important issues. Same-sex marriage rounds out the list with just 41% of Americans saying it's extremely or very important issue in their 2016 presidential vote.

Overall, the recent Supreme Court rulings on same-sex marriage and health care have not significantly increased either issue's salience among the general public. Among Republicans and Republican-leaning independents, however, 45% now call same-sex marriage an extremely or very important issue, up from 34% in February, and 82% consider health care an important issue to their vote, up from 75% in February.

The CNN/ORC Poll was conducted by telephone June 26-28, among a random national sample of 1,017 adults. The margin of sampling error for results among the full sample is plus or minus 3 percentage points. It is 4.5 points for results among the 490 Democrats and Democratic- leaning independents and 5 points for results among the 407 Republicans and Republican-leaning independents.