With Joe Biden’s prospective 2020 run for the presidency, many Democrats believe they have found a sure thing, an “electable” candidate. Biden has name recognition, trustworthiness, and the ability to appeal to a wide swath of the party with the possible exception of its extreme leftmost flank. Supporters say he is the party’s best bet to exorcise Trump from the American soul.

But what if Biden is not the safest choice for Democrats, as some would have it? What if he has limitations that would emerge in the course of a bruising campaign? Every candidate has a flaw or two, of course. But how many does Biden have? Are any of them dealbreakers?

Let’s start by giving the man his due. Joe Biden has served his country for generations. His experience, knowledge, and skills are easily competitive with other 2020 primary candidates. His human qualities are equally impressive. He is a warm, caring person. He has borne his sorrows — including the untimely deaths of his first wife Neilia and children Naomi and Beau — with grace, fortitude, and dignity.

President Obama’s choice of Biden as running mate was inspired. They complemented each other wonderfully, combining age with youth, experience with freshness. We always knew that if (heaven forbid) anything happened to Obama, his replacement would not be a rookie. Biden inspired confidence in the Obama/Biden ticket.

If Biden became the 46th President of the United States, all but the most rabid partisans would sleep well at night. You can trust Uncle Joe not to do anything rash with the nuclear button. If Biden is the nominee, I will vote for him without hesitation. If elected, he will be a steady hand on the tiller.

That said, faults that were forgiven or forgotten during his eight years as vice president are now re-emerging as VP Biden becomes candidate Biden. They include his predilection for touchy-feely, his role in the confirmation of Clarence Thomas to the Supreme Court, his opposition to abortion, his advanced age, his history of gaffes, and finally, his two previous unsuccessful runs in the Democratic primaries of 1988 and 2008.

The touchy-feely issue arouses emotions on both sides and deserves to be carefully parsed. Biden is accused of leaning in, touching, and kissing women without their consent. In prior decades that might have seemed a reasonable extension of his warm and caring persona. But as innocent as Biden’s defenders maintain it to be, it is at the benign end of a spectrum of presumptuous male behavior that makes women’s lives harder, and in the #MeToo era, they no longer have to tolerate it. Biden is not in tune with the times.

People who were horrified by the swiftness and suddenness of Al Franken’s fall sympathize with Biden over the conflation of well-intended physical affection with sexual impropriety. But it would be equally unwise to conflate sympathy with support. The fact that Biden may be getting opportunistically sandbagged by Bernie Sanders supporters is not reason enough, in itself, to vote for him. And all those video clips and still photos of Biden touching women, strung together, would be an attack ad that writes itself.

Women with long memories may have other reservations about Biden. When he chaired the Senate Judiciary Committee during the Clarence Thomas confirmation hearings, he seemed to care more about wrapping up the hearings efficiently than giving fair consideration to Anita Hill. In fact, he suppressed the testimony of three witnesses who were prepared to support Hill’s detailed allegations of sexual harassment, which should have disqualified Thomas from the Supreme Court.

For an unintended-misogyny trifecta, add Biden’s longtime reluctance to support abortion rights. “I don’t like the Supreme Court decision on abortion,” he once said. “I think it went too far. I don’t think that a woman has the sole right to say what should happen to her body.” He later flipped to support Roe v. Wade — but has also supported various infringements on a woman’s right to choose, including repeatedly voting in the Senate for the Hyde Amendment, which prohibits federal funds from being used for abortion.

Age — no, not ageism — is another strike against Biden. He and Bernie Sanders are the two oldest people ever to run for the presidency. If elected, Biden would be 78 on Inauguration Day, nine years older than Ronald Reagan when he took office. As I’ve argued elsewhere, I want a presidential candidate no older than 65. The presidency is an unrelenting 24–7 commitment that requires not only skills and experience, but physical stamina and mental agility. It is reasonable to ask whether a president who will enter his eighties even before completing his first term can withstand the brutal stresses of the job.

A word routinely associated with Biden is gaffe. A web search of “biden gaffes” turns up whole lists from Newsweek, Time, Politico, Fox (of course), and even Britain’s Daily Telegraph. Some of them are charming. “I never had an interest in being a mayor because that’s a real job,” he once said. “You have to produce. That’s why I was able to be a senator for 36 years.” That’s the smiling, self-deprecating Joe we love.

Even so, Biden’s loose lips are legendary. He asked a wheelchair-bound person at an event to stand up for applause. He referred to Obama as “Barack America.” He told a black audience that Mitt Romney would “put y’all back in chains.” On another occasion he said, not altogether tastefully: “I promise you, the president has a big stick.” He prematurely blurted out Obama’s decision to support same-sex marriage, forcing the president to accelerate his announcement.

Other Biden gaffes are more troubling. In 1988, he had to end his first run for the presidency after having been caught plagiarizing parts of a speech given by Britain’s Labour Party leader Neil Kinnock. He also borrowed from a speech by Robert Kennedy. He was nearly expelled from Syracuse University Law School for copying five pages from a law review into a term paper.

We tend to forget Biden’s gaffes because Obama largely banished them. And his slips of the tongue are far less offensive than Donald Trump’s Mount Everest of vicious lies. That Biden has more integrity and decency than Trump is beyond doubt.

But all those verbal mistakes add up to a pattern of imprecision in thought and word. Biden has a big mouth, and without Obama sitting on top of him, it may catch up with him. Republicans will comb through his record with glee, stringing together his blunders into yet another attack ad that writes itself — in the candidate’s own words.

Finally, Biden’s supporters claim he is the only Democrat who can beat Trump. Early polls are always worthless in this regard — we must let the campaigners campaign and the voters vote. But we do know for sure that Biden lost both of his previous presidential primary races. In 1988 he withdrew after the speech mishap, leaving Michael Dukakis to capture the nomination. In 2008 he came in behind Barack Obama, Hillary Clinton, and John Edwards, scoring zero delegates and superdelegates. How exactly does losing — twice — make him “more electable”?

Does having been vice president make Biden a sure thing? Tell that to Richard Nixon (1960), Hubert Humphrey (1968), Gerald Ford (1976), Fritz Mondale (1984), and Al Gore (2000). One might quibble over the details: Nixon lost in 1960 but won in 1968 and 1972. Ford was appointed vice president by Nixon, then elevated to president following Nixon’s resignation, but lost his only presidential election. Gore actually won the popular vote but lost the Electoral College. Still, vice president is not a reliable synonym for future president.

We all love Uncle Joe. But if he really puts America first, he will lay down all that baggage, accept an honorable place in history for his nearly five decades of public service, and gracefully step out of the limelight so that the Democratic party’s ample supply of fresh talent can have its chance to shine. Helping a more viable Democrat capture the White House from Trump might be his last and finest accomplishment.