Many things, most of them unlikely, would have to transpire for former Alaska Sen. Mike Gravel to win the Democratic nomination for president.

A few possibilities: All the other candidates drop out, and no successful write-in campaign is waged. A capricious President Trump orders a catastrophic invasion of another nation, lending massive credibility to Gravel’s perennial anti-war stance (he helped put the Pentagon Papers into the public record). The Democratic primary electorate all of a sudden decides that it would prefer an octogenarian candidate to the current septuagenarian front-runners. (Gravel is 89 years of age; meanwhile, Bernie Sanders is a youthful 77 years old, and Joe Biden is a spring chicken, at 76.)

But last week, Gravel became the 23rd Democrat to count as a “major” presidential candidate by FiveThirtyEight criteria, pushed over the edge from minor to major candidacy by his inclusion in a majority of polls. And that means we have to imagine what we call the “theory of the case” — how can Gravel win the Democratic nomination?

It would be easy to laugh at Gravel’s campaign — while he has said he is running to win, he hasn’t campaigned, and he has turned his operation over to a handful of teenagers who voice his Twitter account with the dually earnest and sneering cadences of the internet. And his political performance art ads have certainly left him open to mockery. But while he’s not likely to win the nomination, Gravel is carrying on a grand American tradition: the protest candidate.

Gravel first ran for president in 2008. He made the debate stage and hit mostly the same note — the cost and senselessness of war and the hubris of American foreign policy. He took to task the major Democratic candidates for their bellicose posturing on Iran and their stances on the invasion of Iraq — Hillary Clinton, John Edwards and Joe Biden had all voted to authorize the invasion. (Last week, Gravel announced an endorsement from “Man Who Threw Shoes At George W. Bush.” Google it.) This time around, Gravel has added to his repertoire, adopting the 2019 left’s fondness for a Green New Deal and the abolition of the Electoral College, along with more niche proposals like postal banking. He is a former two-term United States senator, and while his candidacy is not plausible, it is principled.

Protest candidates can sometimes be spoilers — there’s likely no love lost between Al Gore and Ralph Nader or Hillary Clinton and Jill Stein. Gravel’s protest candidacy is not that kind, but it does suit its age. It has the grassiest of grass roots beginnings, a tinge of absurdity and a devotion to promoting ideas that exist outside the realm of what is currently politically possible.

Gravel’s theory of the case might well be that Democratic voters somehow come to embrace this 89-year-old man with boyish helpmates as an embodiment of the political idiosyncrasies toward which quite a lot of Americans are inclined. (How else do we explain the popularity of Ross Perot in 1992 and 1996?) He’s certainly not making the same case as any other candidate.

At the very least, American politics loves a flame-thrower. Or in this case, a rock-dropper.