Will Hillary Clinton face a serious challenge from the left if (as seems almost certain) she seeks the Democratic nomination for president? I assume she will face a challenge. The hard left represents a major component of her party, and is unlikely to be without a champion during the primary season.

But a serious challenge requires a serious challenger. Who fits that description? Not Socialist Bernie Sanders. Not former Maryland governor Martin O’Malley. Outside of Maryland he’s “Martin Who?” In-state, he’s the guy whose performance met with insufficient approval to keep Republicans — normally a non-factor — from defeating his would-be Democratic successor.

Elizabeth Warren isn’t entirely unserious. But in her one bid for political office she wasn’t a very effective campaigner/debater. In a good year for Democrats and in a very Blue state, she struggled to pull away from Scott Brown.

Moreover, it’s not clear that Warren has the guts to take on Hillary Clinton. Early polls inevitably will show Clinton far ahead of the field, as they did in 2007. In this context, it will require something approaching the brashness of a Barack Obama for a politician with something to lose to enter the Democratic fray.

That’s why John Fund’s suggestion that Jerry Brown will run for president rings so plausible. Brown has never lacked for brashness; indeed, he is a walking embodiment of the trait.

His campaign against Bill Clinton during the 1992 cycle could not have seemed more quixotic when Brown launched it. But Brown proceeded to defeat Clinton in Maine, Colorado, Nevada, Alaska, Vermont, and Connecticut.

More than that, “Governor Moonbeam,” as Brown was then called, nearly drove Clinton crazy. Their clash reminded me of an all-night college BS session in which the smartest guy in the room, try as he might, fails to outdebate the agile flake.

24 years later, Brown would bring more to the table than brashness and mental agility. As Fund says:

If he challenges Hillary Clinton, Brown can claim solid credentials as a liberal leader. He has raised taxes on the rich, been an avid backer of climate-change regulation, and was one of the few Democrats in the country to win white males this past election. “He convinced California voters to support a water bond, a rainy day fund, a reduction in prison sentences, and more,” notes Joel Pollak of Breitbart News. “He is Elizabeth Warren with real executive experience and without the fake heritage.”

Moreover, he just won re-election by 20 points.

Brown, though, will reach the age of 78 in 2016. Though there probably wouldn’t be a “vigor gap” between Brown and Hillary (at least not one that disfavors Brown), his age still would likely be a drawback in the minds of Democratic voters. And although Brown should be able to raise plenty of money and attract quality staff, he still would be significantly outgunned by the Clinton machine.

But even if he didn’t prevail, Brown could still give Clinton something she surely dreads — serious competition. In addition to draining energy and resources, such competition would produce party discord, drive Clinton to the left, and generate more than a few Hillary gaffes. And, at a minimum, a Brown-Clinton matchup would be wildly entertaining.