Will Joe Biden run for president in 2016?

• Biden has run for president twice
• VP is prone to verbal gaffes
• Biden credited with negotiating tough deals

WASHINGTON — Vice President Biden unintentionally promoted himself Saturday night, telling a group of Iowans visiting Washington that he was "proud to be president of the United States."

The crowd, attending a party for President Obama's second inauguration, laughed and applauded as Biden tried to correct himself and then began chuckling.

"Well, there goes that," he said.

Just another blooper for the gaffe-prone veep? Or a more revealing Freudian slip?

Biden has tried for the top job twice but failed to win his party's nomination in 1988 and 2008. If he runs and wins in 2016, he will be 74 on Inauguration Day, making him the oldest man to be inaugurated president.

Even so, he hasn't ruled it out.

"There's a whole lot of reasons why I wouldn't run," he told CNN. "I haven't made that decision. And I don't have to make that decision for a while."

People attending inaugural festivities Monday differed on whether Biden is presidential material.

"I just think that would kind of revert us back to the norm, which was old white guys" running the country, said Robert Thead, 30, a freelance author in Washington, D.C., writing about the millennial generation. "How old is he?"

Pete Epanchin, 40, a fellow at the Environmental Protection Agency, said Biden is "absolutely" presidential. He was pleased to see Biden take a leading role in the administration's efforts to halt gun violence and said it might be easier for Biden to sell that policy than Obama.

"He's a less divisive figure," Epanchin said.

Kisha Webster, 41, a teacher in Baltimore County, Md., said she'd vote for Biden for president. She liked that he reached a compromise with Republicans in December on the "fiscal cliff."

"That's what people want," Webster said. "They want to see a leader be able to work with both sides to help the greater good."

Biden has developed a reputation as a deal maker after 36 years representing Delaware in the Senate, but voters tired of establishment politicians may not view that as an asset.

Gaffes are another issue for Biden, who makes frequent verbal missteps to the delight of late-night talk show comedians.

"He probably wouldn't be diplomatic enough to perform that duty," Jermaine Barnes, 42, a corrections officer from Baltimore, Md., said of Biden's potential to be president.

Some Democrats who watched Monday's inaugural parade said they're waiting to see whether Secretary of State Hillary Rodham Clinton runs for the White House, even though she has said she won't.

Biden "doesn't really energize the base as much as Hillary," said Bridget O'Loughlin, 23, a Georgetown University graduate student from Boston. "Hillary has become a celebrity. Biden is kind of off on his own, being the elder statesman."

Forty-two percent of people have a favorable impression of Biden, and 42% have an unfavorable impression of him, according to a recent survey by Pew Research Center for the People and the Press.

That's lower than the favorability ratings for other recent vice presidents around the time they started their second terms. Dick Cheney's favorability rating was 48 percent in March 2005. Al Gore's rating was 65 percent in January 1997.

Biden's rating is affected by increasing partisanship, said Michael Dimock, director of the Pew center.

And all the jokes about his verbal gaffes may contribute to a perception that he's not a serious person, Dimock said, even though Biden chaired the Foreign Relations Committee and the Judiciary Committee in the Senate.

It's not an "unrecoverable" situation, but turning around public opinion could be difficult for Biden, especially as he continues to play a highly visible role in selling the administration's gun-control policy, Dimock said. The issue is so contentious it may hamper Biden's efforts to expand his appeal to a broader audience, he said.

"It's not like being in this position today is a situation you can't turn around as a public figure," Dimock said. "But certainly, you'd rather have people like you than have people feel split about you, and that's where Biden's been for some time now."