WASHINGTON (AP) — The brash and super-wealthy Donald Trump — who has suffered major financial ups and downs, owns gambling casinos and is thrice married — has shoved his way into the top tier of potential Republican challengers to President Barack Obama next year.

His resume would ordinarily foreclose a run for America’s highest office, but the real estate mogul and reality television figure has used his celebrity to stand out in a crowded field with no obvious favorite. These days, he is ensuring a place in the spotlight by latching onto discredited claims that Obama was born outside the U.S.

Regardless of Trump’s wealth and poll numbers, most political wisdom puts him as a very long shot to win the nomination and with virtually no chance of beating Obama in November 2012. Commentators on both sides of the political spectrum question whether Trump is just engaged in a publicity stunt.

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Karl Rove, architect of George W. Bush’s two presidential wins, has called Trump “a joke candidate.”

Nevertheless, some polls show Trump is strongly challenging presumed Republican front-runner Mitt Romney, a former Massachusetts governor and a successful businessman himself. Trump still has not announced his candidacy. Romney has already taken the first official step toward running.

Trump has shaped himself as an ultraconservative candidate, reversing some positions he once held. He now would make abortion illegal, opposes gay marriage and gun control. He advocates repeal of Obama’s health care overhaul that became law last year. He wants to cut foreign aid, is highly critical of China’s trade and monetary policies and wants to end the U.S. wars in Iraq and Afghanistan.

But he has gotten the most political traction by latching onto the “birther” movement: those who believe claims initiated by the far-right that Obama was born outside the United States — despite the release of official birth records in Hawaii and other evidence. The U.S. Constitution requires that presidential candidates be “natural-born” U.S. citizens.

In recent days, Trump has appeared in interviews on all the major American cable television networks, pushing relentlessly his message that Obama needs to prove he was born in the United States. He points to his rising poll numbers as proof that Americans like what he is saying on that deeply divisive issue.

“I’d like to have him show his birth certificate,” Trump said on NBC television. “And to be honest with you, I hope he can.”

The birther movement has fed on some voters’ festering disaffection with the status quo and economic fears. That’s especially so with those captivated by the antiestablishment, low-tax, small-government tea party movement that sprang to life after the financial meltdown in the fall of 2008, shortly before Obama was elected.

The false assertion about Obama’s birthplace has gained a stunning number of followers. A new poll by the New York Times and CBS television finds that 25 percent of all Americans incorrectly think Obama was not born in the United States. Among all Republicans, 45 percent believe he was born in another country, as do 45 percent of tea party supporters, the poll shows.

Still, while Trump gains political ground with the birthplace issue, other Republicans are avoiding it, fearing it could hurt their party’s credibility.

One of the most conservative Republican governors, Jan Brewer of Arizona, vetoed legislation Monday that would have required future presidential candidates to prove they were born in the United States. Romney and former Minnesota Gov. Tim Pawlenty, who also has taken the first official steps toward announcing his candidacy, have said they believe Obama was born in Hawaii.

Former Alaska Gov. Sarah Palin, the Republicans’ 2008 vice presidential nominee, has supported Trump’s allegations about Obama’s foreign birth. She has not said whether she will run for president. While she maintains a core of fierce supporters, recent polling shows her backing has slipped to single digits.

But public support for, let alone knowledge about candidates this early in the election cycle is fickle, and not many Americans are paying much attention.

A Pew Research Center poll released Wednesday showed 26 percent of Americans named Trump as the potential Republican candidate they have heard most about recently, but 53 percent of Americans surveyed could not name anyone when asked which Republican candidate they had heard the most about in recent days.

Copyright 2011 The Associated Press.