Come on, Joe: Just say no.

Joe Biden, who is reportedly "preparing" for a presidential run, seems like a decent enough guy. He should be proud of his career in public service — including 36 years as a senator and eight years as vice president. But he has no business pursuing the presidency in 2020. For the good of the country, his party, and his own reputation, Biden should bow out of the race long before the voting starts.

It may well be true that with his folksy, everyday guy persona, Biden would have been a better Democratic nominee than Hillary Clinton in 2016. Biden may well have beaten Donald Trump at his own populist game. But for a mix of reasons, some personal and some political, he stayed on the sidelines, and now his moment has passed.

It has passed, for one thing, because Biden is 75 years old and will be 77 during the entirety of the 2020 campaign. He would be 78 by the time the inauguration of the 46th president rolls around in January 2021. That's old in objective terms — eight years older than our current septuagenarian president was when he took the oath of office. And in the specific case of Biden, it really shows. His passionately anti-Trump speech at the 2016 Democratic convention was warmly received, but he already sounded somewhat doddering in places. That would certainly be worse when he's four years older, and especially in unscripted settings. The man with a longstanding, well-earned reputation for embarrassing and sometimes insulting verbal flubs would become a one-man gaffe machine that the Trump campaign would delight in exploiting.

And remember: This wouldn't be a modest come-down for a once-formidable presence on the campaign trail. Biden has run for president, and gone absolutely nowhere, twice — in 1988 and again in 2008. Why would we expect him to connect more powerfully with voters now, when he'll be a decade past the traditional retirement age? Just because he's a selectively charming old white guy with an impressive resume?

Every one of those qualities is likely to be a liability for a Democrat aiming to defeat President Trump in 2020.

Even worse: Biden is very much a man of his generation in his tendency to get a little handsy with women. That would be bad enough in the #MeToo era. But when it's combined with his decidedly chilly attitude toward Anita Hill while chairing the Senate Judiciary Committee's hearings on Clarence Thomas' nomination to the Supreme Court back in 1991, we're left with a candidate quite likely to antagonize women in 2020.

This would be especially true for younger women, who would find the abundant documentary evidence of all this in the form of YouTube videos more than a little creepy — and a sign that Biden comes from and speaks for a generation with a very different, and quite archaic, cultural outlook.

That would only add to Biden's generational problems. At a time when young Democrats are clamoring for bold and aggressive moves on economic and social policy to address income stratification and rampant economic injustice, Biden's record looks incredibly complacent. He has no history of supporting any progressive reforms — and a long history of close ties to Delaware's powerful financial services industry.

Republicans may be willing to treat a trash-talking real estate mogul as if he's a populist, but Democrats prefer their champions of the working class to do more than make aw-shucks references to growing up in Scranton, Pennsylvania, in the 1940s and '50s.

Maybe Biden would have some success in peeling away some of Trump's support among elderly voters in the Midwest. But the future of the Democratic Party is found among the young. Mobilizing youthful voters doesn't require a candidate who's young, or female, or non-white. (Just ask Bernie Sanders.) But it does require a candidate who's willing and able to shake things up, to break from a sclerotic status quo, who recognizes how in-grown, cautious, and reactive Democrats have become in the decades since Ronald Reagan yanked the political spectrum to the right. Those younger voters think it's long past time to yank America to the left, and they want a candidate who is eager to do exactly that.

Joe Biden simply isn't that kind of candidate. Which is why we'd all be better off if he made room in what is sure to be a very crowded field by stepping aside before the real contest begins.