The most consequential election of our lives may end in a photo finish. Many progressives who backed Bernie Sanders support Jill Stein or plan on staying home. I write to implore them to vote for Hillary Clinton; for our country’s and our planet’s sake and because, for progressives, it’s the smart move.

I served as counselor to the president in the Clinton White House but backed Bernie to the last day of his improbable, inspiring campaign. I did so because I believe we cannot endure, politically or economically, without reforming global finance capitalism and the pay-to-play politics it feeds on. I still believe it.

Among the political choices I’ve had to make, the one between Clinton and Trump isn’t the happiest, but it’s still the clearest. The big reason is, of course, Trump. To the media’s lasting shame, he snatched a major party nomination without serious vetting. Many still won’t tell the truth about him; that he’s emotionally unbalanced, a fascist, and a fraud.

I’ve never before called a politician a crazed fascist. But this is no time for politesse. Look up “narcissistic personality disorder” on Wikipedia, and you’ll find everything but Trump’s picture. Scholarly essays on fascism read like Trump playbooks. His latest big lie: the election’s rigged. His remedy: sending “poll watchers” to black voting districts. The likely volunteers: white nationalists. What could go wrong?

Some progressives equate military hawkishness and pay-to-play politics with fascism. Fascism is ideologically nondescript; a fascist can be for or against single payer health care, global trade or the Iraq war. Its trademarks include annihilating the truth; defaming minorities; inciting violence; using government to punish opponents and quash dissent; hyper-nationalism; and grandiosity. Trump checks every box. He isn’t Hitler, but he’s sure within shouting distance of Mussolini. The sacred duty of every citizen is to kill fascism in its crib.

Greens say the election isn’t a binary choice, but the high stakes make it one. The next president may name two Supreme Court justices. Some progressives seem bored by this point. The current Court makes more law than the moribund Congress. One Trump justice saves Citizens United. Two would mean the end of Roe v. Wade. It’s an awful price to pay, and still not the biggest.

That would be climate change. It’s happening way faster than most early models predicted. If we don’t act decisively the loss of major coastal cities is assured, as are disease, drought, famine, and war. The Democrats’ record on climate change is highly mixed. Obama opened more federal land to oil and gas drilling in two years than Bush did in eight. But his recent rhetoric is stellar, and in China and Paris he showed leadership.

Clinton’s record doesn’t impress but her platform is notable for its specificity. A strong grassroots movement could push her further. If Trump wins, movement building is beside the point. If he rips up the Paris accord and “brings back coal,” any hope of averting the worst environmental disaster in human history is lost.

Other differences are nearly as profound. If you don’t think the rights of all persons of color will be far better protected by Hillary Clinton than Donald Trump you’re in denial. If Trump gets his massive tax cuts for corporations and the super-rich, he’ll forever settle the argument over whether income inequality is worse now than in the Gilded Age. If Clinton gets her tax package and raises the minimum wage to $12 or more, it will be one of the biggest, best-targeted income transfers ever. Even if you don’t admit Trump’s fascism or the planet’s peril, these are things worth compromising for.

The most heated arguments against Clinton pertain to character. When cornered, her first instinct is to dissemble. As I’ve noted, she denies a vital truth; that saying you can take bundles of Wall Street cash and still fight for the middle class is like thinking you can smoke crack and still be a good parent. The conflict is at the heart of all that is wrong in our politics. But these real flaws pale next to Trump’s pathological lying and plutocratic greed.

When the left stoops to the ugly personal invective of the right, I recoil. I’ve seen Clinton close up. Her empathy is genuine. The loyalty of the people closest to her is deeper than I’ve seen for any other politician. Everyone who ever worked for her is out doing all she or he can to elect her.

The only way to win such devotion is by treating everyone in your life with love and respect. It must count for something.

The weakest arguments against her are tactical. Noam Chomsky says he’s voting for Jill Stein but if he lived in a swing state he’d vote for Clinton. It’s not enough. A razor thin popular vote margin for Clinton would trigger months if not years of civil unrest, while a bigger win could give Democrats the Senate. I’m of the (minority) view that if they take the Senate, Democrats can influence the House by winning just 15 or so of the 30 seats they’d need for outright control (nothing gets the herd’s attention like a good culling).

Some progressives actually say they’d be better off with Trump. A popular theory is that his reign would trigger a populist revolt. But a Trump victory would leave many liberals embittered and despondent. Few would leave the country, but many would leave politics in search of other ways to heal the world.

It is a tragedy of our politics that the real debate begins the day after the election. Starting Wednesday there will actually be two debates, one in each party, over the identity of each. Some say a Clinton win entrenches party elites. I think not. In the 1990s Bill Clinton held the party together by force of personality. For eight years Obama did the same. The guy holding them together now is Trump. He won’t after Tuesday. Nor will Clinton. She hasn’t the charisma, and the time for it is past. Her election would energize and empower progressives. She knows it even if they don’t. If she forgets we’ll remind her. If she forgets too often we’ll primary her. She knows that too.

America needs a strong, independent progressive movement. Historically, progressives were better off when their relations with Democrats were more arm’s length. When they traded the politics of pressure for the politics of access starting in the early 1980s, they grew weak. Many withdrew into mere protest politics. That hasn’t worked out either. In 2012 Jill Stein got .339 percent of the vote. Tuesday, more millennials will vote libertarian than Green. Progressives must learn to vie for power. They can start now by asking which outcome best serves their cause.

We scorn Republicans who say they’ll vote for Trump but not endorse him, but we on the left who denounce him but act in ways that help him are no different. It really is the most important election of our lives. Tuesday morning I’ll vote for Hillary Clinton. I’ll rejoin the opposition Tuesday night, 8:01 p.m., Pacific Time.

Bill Curry is a former Clinton White House official and two-time Democratic candidate for governor of Connecticut.