Despite the feverish stream of strategic leaks in recent days, there are still very real questions about whether Vice President Joe Biden will ultimately decide to jump into the presidential race, or whether he’s merely positioning himself as a backup in case Hillary Clinton falters.

But if Democratic voters who are feeling lukewarm about Hillary see the veep as a potential white knight—either because he’s more liberal or because he’s more electable—they could be in for a rude awakening.

Biden has been a loyal and effective vice president—and a recent personal tragedy of unimaginable proportions is generating broad sympathy for him and his family right now. But over his long career, Biden’s record is hardly that of a progressive crusader. And his candidacy would perhaps pose more political problems for the Party than it would solve.

Related: If Biden jumps into the race, who will Obama support?

Here are 10 reasons why Joe Biden isn’t going to be progressives’ savior—and why a Biden campaign could even make it harder for Democrats to hold the White House:

1. Biden was the main Senate author of the 1994 Violent Crime Control Act, which, among other steps, encouraged states to incarcerate more people. There’s now widespread agreement that that approach was disastrous. “We now know with the fullness of time that we made some terrible mistakes,” one expert said last year in reference to the law. “And those mistakes were to ramp up the use of prison.” Today, Biden supports legislation to reduce mandatory minimum sentences.

2. As a young senator in the 1970s, Biden pandered to conservative constituents by turning himself into a “leading anti-busing crusader,” as one chronicler of the episode recently put it. Speaking in support of an anti-busing amendment offered by the segregationist Sen. Jesse Helms, Biden called busing “a bankrupt concept.” His opposition would help shift Democrats away from a forthright stance in favor of de-segregation policies.

3. Biden has frequently voted to ban so-called “partial-birth” abortions, and has avoided voting when other abortion legislation was being considered. He said in 2008 that he believes life begins at the moment of conception, though he wouldn’t impose that judgment on everyone.

4. As Senate Judiciary chairman, Biden angered some women’s rights advocates with his handling of Clarence Thomas’s contentious 1990 confirmation hearings, in which Thomas was accused of sexual harassment by a female subordinate, Anita Hill. Biden didn’t allow testimony from two of Hill’s female colleagues who would have corroborated Hill’s claims, but he did allow a parade of witnesses to challenge Hill’s credibility, often in flatly sexist terms. (One suggested Hill might suffer from “erotomania.”)

5. Biden’s home state of Delaware is home to numerous credit card companies, and he has a long history of support for the banking industry. He was a lead sponsor of an industry-backed 2001 bill that would have made it much harder for struggling Americans to declare bankruptcy, and voted for a similar 2005 measure that passed. Among the leading opponents of those bills? A Harvard law professor named Elizabeth Warren.

6. Biden voted for the Iraq war. Clinton’s vote for the war was perhaps the single most important reason she ultimately lost the Democratic presidential nomination in 2008 to Barack Obama. Both Biden and Clinton have since said it was a mistake to trust President Bush to conduct the war effectively.

7. When Biden and Clinton both served in the Senate, from 2001 to 2009, his voting record was generally slightly more conservative than hers, according to statistician Nate Silver.

8. There’s little policy rationale for Biden’s candidacy. On the economic issues that are most important to many Democrats right now, Clinton’s proposals to date have been relatively strong. Not much in Biden’s background—save one meeting with Elizabeth Warren—suggests he’d be well-suited to run to the left of her. Any effort to do so would involve wresting voters away from Bernie Sanders—a more credible messenger for progressive economic policies.

9. Policy positions aside, there’s currently little reason to think Biden would offer Democrats a better chance of keeping the White House than Clinton, as Silver recently explained. He generally performs worse than her in head-to-head polls against Republican contenders, and his personal favorability ratings are no better than hers, even though he’s faced far less scrutiny from the press and the GOP. His two previous presidential bids, in 1988 and 2008, were flops (in the first one, he quit the race after plagiarizing a speech from a British politician). He’s never been a prodigious fundraiser. His habit of touching younger women in public has raised eyebrows. And he’d be 74 by the time he was inaugurated, making him by far the oldest president to take office.

10. A Biden candidacy at this point in the race would lend steam to the questionable notion that Clinton’s use of a personal email account is a major scandal, helping paint a picture of a fatally damaged Democratic front-runner. And it would split the Democratic party, much of which is already behind Clinton. Because there aren’t many clear policy differences between the two (see Number 8), Biden would likely have to argue that Clinton isn’t trustworthy enough to be elected, which could trigger a particularly bitter and divisive campaign. President Obama would be placed in a near-impossible position, stuck between his vice president and his one-time secretary of state—a dynamic that’s already begun. Add to that the spectacle of a man preventing history from being made by trying to nudge aside a woman seen to have paid her dues, and it’s a potential recipe for Democratic suicide.