Washington (CNN) Some 2016 presidential hopefuls have already outlined an agenda of what they would do on their first day in the White House -- and many have set their sights on the Iran nuclear agreement. The controversial deal on Wednesday secured the pledged support from Democrats in Congress it needed to prevent Republicans from scuttling the agreement.

Other candidates' day one agendas, meanwhile, include actions as varied as repealing Obama administration executive orders to hosting a pig roast on the White House lawn.

Scott Walker

Wisconsin Gov. Scott Walker says that if he were elected president, the U.S. would halt negotiations with Iran and pull the nuclear deal.

"As president, on my very first day going forward, I would pull back -- I would terminate that bad deal with Iran completely on day one," Walker said on Fox News hours before the landmark deal was announced in June. "I would then put in place crippling economic sanctions against Iran, and I'd convince our allies that this is not a country we should be doing business with."

Walker took his "day one" promise further while speaking to reporters at the Family Leader Summit Saturday, saying that the next president will need to take action against Iran on day one in the White House and this will "very possibly" include military strikes.

Walker's remarks came as his advisers suggested Republican presidential candidate Jeb Bush is softening his stance on Iran -- a claim that Bush advisers deny.

America needs a President who will approve the #KeystoneXL pipeline on the very first day in office. #Walker16 — Scott Walker (@ScottWalker) August 6, 2015

Jeb Bush

Bush has not made a promise about what he would do on day one, but he did outline one thing that he wouldn't do: tear up the Iran deal.

"One thing I won't do is just say as a candidate: 'I'm just going to tear up the agreement on the first day.' That sounds great, but maybe you ought to check in with your allies first," Bush said at a campaign event in Carson City, Nevada, in July. "Maybe you ought to appoint a secretary of state, maybe a secretary of defense. You might want to have your team in place before you take an act like that."

Bush added that he thinks "it's important to be mature and thoughtful about this."

While Bush offered strong criticism of the deal, his view is starkly different from Walker, Carly Fiorina and fellow Florida politician Sen. Marco Rubio.

Marco Rubio

Rubio said that on his first day in office he would cancel the deal, even if he does not have the support of the United States' European allies, in an interview with NPR in April.

The Florida senator said he would "simply re-impose the sanctions" on Iran that would have been lifted as a part of the Iran deal.

"What the President is banking on is that he's going to use a national security waiver to lift the sanctions on Iran, the economic sanctions that now exist. And we would simply re-impose the sanctions," Rubio said.

However, if Congress and the Iranian Parliament approve the deal, sanctions on Iran will not be lifted immediately and may not be lifted by January 2017. Based on the conditions outlined in the deal, sanctions on Iran will be lifted in phases once Iran holds up its end of the deal -- implementing the restrictions on its nuclear program and reducing its nuclear capacity.

On Wednesday, Rubio tweeted: "When I'm president, we won't just reverse President Obama's dangerous Iran deal. We will increase sanctions on Iran."

When I'm President, we won't just reverse President Obama's dangerous Iran deal. We will increase sanctions on Iran. — Marco Rubio (@marcorubio) September 2, 2015

Carly Fiorina

The former Hewlett-Packard CEO -- who is the only Republican woman running for president -- has also made the United States' relationship with Israel a focus on her foreign policy.

Fiorina recalled a private meeting she had with Israeli Prime Minister Benjamin Netanyahu to discuss Iran and said that on her first day in office, she would call both Netanyahu and Iran's Ayatollah Khamenei.

"I would make two phone calls, day one, in the Oval Office. The first would be to Bibi Netanyahu. The second would be to the Supreme Leader of Iran. And while he might not take my phone call, he would get the message," Fiorina told Fox News in May. "And the message would be until and unless you are prepared to open every nuclear facility, every uranium enrichment facility to full, untethered, anytime, anywhere inspections, we will exact the most punishing financial sanctions we can."

Rick Perry

At the first GOP presidential debate for second-tier candidates last month, former Texas Gov. Rick Perry said he would tear up the Iran nuclear deal on day one when candidates were asked what their first executive order would be.

"It'll be a pretty busy day, but that Iran negotiation is going to be torn up on day one," Perry said. "We're going to start the process of securing that border. I'm also going to take a bottle of White-Out with me to get started on all those executive orders that Mr. Obama has put his name to."

And while announcing his second bid for the presidency in Addison, Texas, in June, Perry said that if he were elected president, he would approve the Keystone pipeline on his first day in office.

He also promised to authorize natural gas exports and "issue an immediate freeze on pending regulations from the Obama administration," referring to the White House's proposed regulations on carbon dioxide.

Perry added that on day one, he would also "sign an executive order authorizing the export of American natural gas and freeing our allies from the dependence of Russia's energy supplies."

Rand Paul

Kentucky Sen. Rand Paul, who has long led a crusade against the National Security Agency's bulk surveillance of Americans, said that he would end the NSA's mass surveillance on his first day in office.

"The phone records of law-abiding citizens are none of their damn business," Paul said during his presidential announcement in Louisville, Kentucky, in April. "And as president on day one, I will immediately end this unconstitutional surveillance."

The month following his presidential announcement, Paul gave a nearly 11-hour speech on the Senate floor in May, calling for the repeal of NSA surveillance programs authorized under the Patriot Act.

Ted Cruz

Texas Sen. Ted Cruz was asked by Breitbart News , a conservative news outlet, whether "one of the first things he would do if elected would be to undo all of Obama's unconstitutional executive orders."

"If I am elected president, the very first thing I intend to do on the first day is rescind every single unconstitutional or illegal executive action from President Obama," Cruz said.

Obama's executive action on immigration is one of the moves that Cruz has harshly criticized.

"One of the things the President has claimed, rather absurdly, is that the basis of his authority is 'prosecutorial discretion.' That he's simply choosing not to prosecute 4.5 million people here illegally," Cruz told Fox News in February.

And at a town hall at Southern University of New Hampshire in May, Cruz also shared a more light-hearted agenda that he plans to fulfill his first day in office.

"Let me start by saying if I'm elected, January 2017, I suppose the first thing I should do is send flowers and a note of condolences to all of the reporters and editors who've checked themselves into therapy," Cruz said, poking fun at the press, amid laughter and applause from the crowd.

"And frankly, the second thing I would do, is start planning -- if you're going to let a Cuban into the White House -- start planning for December 24, 2017, when I guarantee you we would have a pig roast on the South Lawn of the White House," Cruz added.

George Pataki

At the first Republican presidential debate for second-tier candidates, former New York Gov. George Pataki said that he would revoke all executive orders issues by President Obama on his first day in office.

"I defeated Mario Cuomo, and the first day in office, my first executive order, I revoked every one of the executive orders that he had enacted over the past twelve years. I would do that to Barack Obama's executive orders," Pataki said.

However, Pataki did not, in fact, revoke "every one" of Cuomo's executive orders.

Martin O'Malley

Former Maryland Gov. Martin O'Malley will not be overturning Obama's executive actions if he enters the White House. In fact, on day one in office, he promises to begin implementing a comprehensive immigration reform plan that paves the way for a pathway to citizenship.

"Comprehensive immigration reform means yes, sure, protecting our borders, protecting public safety but having a path to citizenship for all of those millions of our neighbors who have been caught in the switches," he told immigration activists in New York. "The pathway should be the ability to actually find the line that's actually a line and be able to become a citizen in fairly short order."

O'Malley pledges to use his executive authority, if elected, to provide "immediate relief' to immigrants by implementing short-term immigration reforms, much like Obama did early this year.