Vice President Joe Biden can only think of one reason not to run for president in 2016: He wouldn't be able to drive Corvettes. That's it. We went ahead and thought of several others.

Biden's remarks came during an interview with CNN's Kate Bolduan. Riffing off of Biden's comments at a gathering of the United Auto Workers, Bolduan brought up those Corvettes and Biden's excitement about their acceleration. (Zero to 60 in 3.4 seconds? "That's right, man!") Biden said he was otherwise ready to go, and would decide at some point next year whether or not he'd actually run. And that would depend on whether or not he was "the best qualified person" to address his life's two main issues: giving "ordinary people a fighting chance to make it" and "sound foreign policy" where the U.S. is known "not only for power of our military, but the power of our example."

Well, we don't mean to rain on Biden's drag race to victory, but it's obviously not that simple.

History is against him.

In the past century or so, seven former vice presidents have become president. Which sounds good in the abstract. But in reality, it's daunting. Only George H. W. Bush was elected to replace the man under whom he served. That's it. One. Richard Nixon became president years after leaving the White House. And Presidents Ford, Johnson, Truman, Coolidge, and Teddy Roosevelt all stepped up after the president died or was killed in office.

He's not very popular.

The presidency is the country's biggest and best-established popularity contest. And Biden's not doing that well at it.

His most recent favorability rating puts him underwater, with 40 percent of Americans approving of his job performance and 48 percent disapproving. That's hardly set in stone, of course, but the trend is bad; he's consistently grown less popular since the second inauguration. The last time he was in net positive territory — more approval than disapproval — was last April.

Not everyone agrees on his core competencies.

Biden's two-prong pitch — his fight for working people and his push for better foreign policy — might be tough to sell. Robert Gates, former secretary of defense under Presidents Obama and Bush, recently published a book excoriating Biden, saying that the vice president "has been wrong on nearly every major foreign policy and national security issue over the past four decades." The book outlines ways in which Gates thinks Biden undermined the defense department's efforts in Iraq and Afghanistan. And the book has been at the top of the best-sellers list for two weeks.

In 2008, foreign policy was Biden's selling point, one of the reasons Obama picked him as his running mate. In 2016, that working class, Ed-Schulz-but-with-power advocacy might be better. Because of the number one obstacle Biden faces.

Hillary Clinton exists.

Everything about that CNN video was actually about Hillary Clinton. The thing about the Corvettes? Biden's subtle dig at Clinton's not having driven in two decades. The "working class" thing? About how the Democratic Party has largely shifted to the left, away from the famous centrism of the Bill Clinton era.

Clinton is no more a sure thing now than she was in 2006, and her possible/probable/who-are-we-kidding-all-but-certain candidacy shouldn't be a reason for anyone not to run. But Biden still trails her in most measures. A poll last month had Clinton up 61 points on the vice president. Even after many of the revelations about New Jersey Gov. Chris Christie's behavior in the George Washington Bridge scandal came out, Biden trailed him by 11. And at PaddyPower, an Irish gambling site where people actually put money down on prospects, Biden trails Elizabeth Warren — who has said explicitly that she won't run.

Running for president — being president — has always been Joe Biden's dream. It's tough to give up on your dreams, as we can all appreciate. But if the question is really that Biden can't think of any reason not to do it, well, he hasn't thought very hard.