WASHINGTON (AP) -- Bring on Donald Trump, and Ben Carson, too.

That's what Democratic insiders are saying about the Republican outsiders who sit solidly atop preference polls in the race for the GOP nomination for president.

They are far more worried about GOP candidates who have experience in office, with Marco Rubio cited most often as the strongest potential competition for their overwhelming choice for the Democratic nomination, Hillary Rodham Clinton.

"As a Democrat, I'd love to see a Trump-Carson ticket," said Bob Mulholland, a member of the Democratic National Committee from California. "We'd probably win back the Senate and pick up the House as well."

The Associated Press contacted all 712 superdelegates to the Democratic National Convention next summer, and asked them which Republican they thought would be their party's strongest opponent in the general election.

Offering a window into how the Democratic establishment is sizing up the competition, most superdelegates declined to name a candidate, expressing bewilderment at a Republican field in which billionaire Trump and retired neurosurgeon Carson are leading in polls while Jeb Bush, the son and brother of presidents, struggles.

Of the 176 superdelegates who answered the question, 65 said Rubio, the first-term senator from Florida, would be the Democrats' strongest opponent.

"Rubio speaks well and he could generate appeal among Latino voters," said Chris Wicker, vice chairman of the Nevada Democratic Party, referring to Rubio's background as a Cuban-American raised by working-class parents. "He doesn't say some of the crazy stuff that the other leaders have said."

The other candidates, along with the number of Democratic insiders who said they would be the strongest opponent:

Ohio Gov. John Kasich: 45.

Bush: 36.

Trump: 16.

Carson: 4.

Texas Sen. Ted Cruz: 4.

New Jersey Gov. Chris Christie: 2.

Businesswoman Carly Fiorina and former New York Gov. George Pataki each got a vote. So did Wisconsin Gov. Scott Walker, who dropped out of the race, and Mitt Romney, the 2012 Republican nominee.

Democratic superdelegates can support the candidate of their choice at the party's summer national convention, regardless of whom voters choose in the primaries and caucuses. They are members of Congress and other elected officials, party leaders and members of the Democratic National Committee.

They are the ultimate party insiders. With 712 votes at the convention, superdelegates make up about 30 percent of the 2,382 needed to clinch the Democratic nomination.

Rubio, 44, has done well in preference polls lately, but he still lags behind Trump and Carson. Some Democratic insiders worry that Rubio's candidacy could resonate in the general election, particularly among non-white and young voters who helped propel Democrat Barack Obama to victory in 2008 and 2012.

"I think Rubio would give us a tough time," conceded Cecil Benjamin, state Democratic chairman of the Virgin Islands.

In an interview, Rubio played down his status among Democratic insiders.

"You never know what these people are thinking when they say these things to reporters," Rubio said. "I do believe, and I've believed this through this campaign, that if I'm our nominee, we're going to be viewed as the party of the future and the Democrats are going to be viewed as the party of the past."

In the AP survey, many Democrats were dismissive of Trump. Some said his sharp rhetoric on issues like immigration, which is playing well among some Republican primary voters, won't fly in a general election.

"He's a loose cannon," Missouri superdelegate Sandra Querry said of Trump.

"Like everybody else in America," Georgia Democrat Dan Halpern said, he's "just wondering when the wind is going to come out from under the sails of both Carson and Trump."

In the last GOP presidential debate, Bush criticized Trump's call for mass deportations of immigrants living in the country illegally, calling it an impractical plan that would benefit Democrats with Hispanic voters.

"They're doing high-fives in the Clinton campaign right now when they hear this," Bush said.

Indeed, Clinton spokesman Brian Fallon responded to the exchange by tweeting: "We actually are doing high-fives right now."

The Clinton campaign said it had no comment on the strength of individual GOP candidates, saying they were all equally "out of touch" with voters.

About one-fifth of Democratic superdelegates who answered the survey said they believe Bush, who is fighting to stem a slide in GOP polls, could bounce back and pose a threat to Clinton, given his name recognition and early fundraising.

Even more superdelegates praised Kasich, a two-term Ohio governor who served 18 years in the House. Some Democrats described Kasich as the "adult" in the field who could campaign from the center and win his home state, a key battleground.

The last candidate to win the White House without Ohio was Democrat John F. Kennedy in 1960.

"A Democratic nightmare would begin and end with a Rubio-Kasich ticket," said former state Rep. Boyd Brown of South Carolina.

The AP results come as Clinton is solidifying her support among the superdelegates. More than two months before the first primaries and caucuses, Clinton has public endorsements from 359 superdelegates, while Vermont Sen. Bernie Sanders has 8 and former Maryland Gov. Martin O'Malley has 2.

A few Clinton supporters warned against dismissing Trump too quickly, given today's political climate.

Joe Rugola, a labor union leader in Ohio, said Trump and Carson might be written off in a normal political year, but "I don't think there's anything normal about politics in America right now."

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Associated Press writers Julie Pace in Washington; Elliot Spagat in San Diego, California; Michelle Rindels in Carson City, Nevada; Ben Fox in Miami; Summer Ballentine in Jefferson City, Missouri; Kathleen Foody in Atlanta; Meg Kinnard in Columbia, South Carolina; Julie Carr Smyth in Columbus, Ohio; Alanna Durkin in Richmond, Virginia; and Deepti Hajela in New York City contributed to this report.

© 2015 The Associated Press. All rights reserved.