Even as Martin O’Malley’s presidential crypto-campaign bandwagon–generally considered the most advanced and viable this side of the imaginary campaign of Elizabeth Warren–hit a potential pothole on the mean streets of Baltimore this week, Vermont Sen. Bernie Sanders made it official: he’s in.

One threshold question Sanders will have to face in getting himself taken seriously is why he’s making his first race for the presidency at the age of 73. He could plausibly say it’s taken the events and political dynamics of the last eight years to make his previously exotic self-identification as a “socialist” a badge of honor.

Beyond that, Sanders is probably the right person to challenge HRC’s electability argument with the longstanding but rarely tested (at least at the national level) electability claim of the Labor Left: that a lot of independents and even Republicans would be attracted to an agenda with items like single-payer health care (“Medicare for All”) and a pledge to insulate American workers from low-wage overseas competition.

As for what his candidacy means for HRC, I would guess he’s exactly the kind of rival she’d hope for if she has to have one: a genuinely nice guy who probably won’t cooperate with Republicans by hurling personal epithets at her. That’s important, because she might have drawn an opponent who shares the unfortunate tendency of some lefty folk to believe any Democrat who doesn’t share their self-evidently correct views on every topic is either a coward or a whore. I would also guess that Sanders will react positively and graciously if HRC takes positions closer to his than is expected, instead of treating her as a coward or whore who’s running scared.

Inevitably the question will arise: is Sanders a “serious” candidate? Matt Taibbi may be right in saying that the media could make Sanders “serious” if they’d just stop dismissing him because he’s not raising tons of money. As it is, he is an abundantly qualified candidate representing a legitimate POV that’s well established, historically and in current public opinion, within the Democratic Party. That’s a serious matter.

Ed Kilgore

Ed Kilgore is a political columnist for New York and managing editor at the Democratic Strategist website. He was a contributing writer at the Washington Monthly from January 2012 until November 2015, and was the principal contributor to the Political Animal blog.