Susan Page and Jenny Ung

USA TODAY

WASHINGTON — Vermont Sen. Bernie Sanders fares a bit better than rival Hillary Clinton in head-to-head matchups against Republican presidential contenders, a USA TODAY/Suffolk University Poll finds, and he has pulled within 10 percentage points of her for the Democratic nomination.

The nationwide survey, taken Thursday through Monday, underscores how formidable an opponent the 74-year-old democratic socialist has become against one of the Democratic Party's most established figures.

Clinton — a former first lady, two-term New York senator and secretary of State — is backed by 50% of likely Democratic primary and caucus voters, down 6 points from December. Over that time, Sanders' standing has surged 11 points, to 40%.

While Clinton argues that she would be more electable in November, Sanders shows somewhat more strength against four possible Republican opponents, although almost all of the matchups fall within the poll's margin of error of plus or minus 3 percentage points.

Meanwhile, the Republican race has become a three-man contest. Real-estate mogul Donald Trump has widened his lead nationwide to 35% of likely Republican voters, with Texas Sen. Ted Cruz at 20% and Florida Sen. Marco Rubio at 17%. The other three Republican contenders — Ohio Gov. John Kasich, former Florida governor Jeb Bush and retired pediatric neurosurgeon Ben Carson — trail in distant single digits.

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The presidential race in both parties has been defined and sharpened by the opening Iowa caucuses and New Hampshire primary this month.

"The New Hampshire primary was more than just the allocation of a few party delegates from a small state," says David Paleologos, director of Suffolk University Political Research Center in Boston. "We are finding shifts in national opinion from coast to coast, and what happens next in Nevada’s caucuses and the South Carolina primaries also will have an impact.”

Sanders' double-digit victory in New Hampshire has propelled his candidacy and heightened the stakes for Clinton to score clear victories in the Democrats' caucuses in Nevada on Saturday and primary in South Carolina next week. In the GOP, Bush and Kasich will face growing pressure to suspend their campaigns — as eight of their rivals have done in recent weeks — unless they manage to finish in the top half of the field in the Republican primary in South Carolina on Saturday. Carson, who briefly topped national polls last fall, now sits at the bottom, at 4%.

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"I would vote for Trump, Rubio or Cruz, but I prefer Rubio because I like the way he stands, his policies, and he's young," Lindsey Dickson, 62, who works for a credit union in Phoenix, said in a follow-up phone interview. She was among those surveyed. "I like what Trump has to say. He's honest and at the end, he just goes full speed ahead."

When Republican voters' first and second choices are combined, giving a sense of what might happen is the field winnows, the trio's advantage at the top gets bigger and their contest gets closer. Trump is the first or second choice of 44% of Republicans; Rubio and Cruz of 40% each.

The margin of error for the sample of 319 likely Democratic primary and caucus voters is plus or minus 5.5 percentage points. The margin of error for the sample of 358 likely Republican voters is plus or minus 5.2 percentage points.

In hypothetical matchups in the general election:

• Clinton loses by 2 points to Trump (43%-45%), 1 point to Cruz (44%-45%), 6 points to Rubio (42%-48%) and 11 points to Kasich (38%-49%). That's a weaker standing than the former secretary of State showed in December's survey, when she narrowly led Trump and Cruz and trailed Rubio by just 2 points.

• Sanders loses by 1 point to Trump (43%-44%), 3 points to Kasich (41%-44%) and 4 points to Rubio (42%-46%) — each of them a slightly stronger showing than Clinton — and he leads Cruz by 2 points (44%-42%).

Kevin Baugh, 31, a web developer from Austin, Texas, is inclined to back Sanders over Clinton, in part because of concerns about her fundraising. "I'm kind of weary of her," he says. "It makes me uncomfortable to support a candidate who is potentially in the pocket of big corporations."

Voters in the two parties are looking for different things in the next president.

Democrats by an overwhelming 7-1 say they prefer a presidential candidate with government experience over an outsider who is a fresh face to politics. But Republicans by double digits, 48%-37%, say they prefer a fresh face — a sentiment that helps explain Trump's continued dominance over rivals with more traditional résumés for the presidency.

That's why Forman Dubois, 36, a union laborer from Freehold, N.J., is backing Trump. "I want to get away from everybody who's already a politician," he said.

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In both parties, a majority say they would prefer a candidate who advocates a more limited agenda but promises to get it done over a candidate who offers a more ambitious agenda.

In the Democratic race, Clinton and Sanders are tied among men, 44%-44%, but Clinton holds a double-digit lead among women, 54%-36%. Sanders has a wide advantage among younger voters, 18 to 34 years old, of 59%-34%. But Clinton leads among every other age group, a gap that gets particular wide among seniors 65 and older.

Angela Riley, 53, of Minneapolis, is likely to vote for Clinton. "Bernie is a little too far to the left, a little too socialist," she says. "His age concerns me as well."

But Tom Eberhardt, 32, who works for an insurance company in Stevens Point, Wis., is leaning toward Sanders. "I like that he has some new ideas that will potentially bring up changes in such a screwed-up political system," he says. While he generally agrees with Clinton on issues, "I'm not crazy about the fact that she's such an establishment politician."

Asked to name the most important issue facing the next president, just two concerns dominated all the rest. Democrats most frequently cited jobs and the economy, Republicans terrorism and national security.