Show me the fever, into the fire, taking it Steyer and Steyer. Photo: David Paul Morris/Bloomberg via Getty Images

Tom Steyer was the single biggest liberal donor in America’s last two federal elections. In 2016 alone, the billionaire investor plowed more than $91 million into the coffers of Democratic candidates — often on the condition that said candidates were willing to pledge their support for an ambitious agenda to combat climate change.

But Democrats who want Steyer’s money in 2018 will need to promise to take radical action against a very different threat to humanity — the presidency of Donald J. Trump.

In a letter to the Democratic Party’s congressional offices, and House and Senate campaign committees, Steyer argued that Trump presents a “clear and present danger to the republic,” and called on candidates to “make your position clear so that Democratic voters who are under constant attack by this administration, know their elected representatives have the patriotism and political courage to stand up and take action.”

In the letter, which was obtained by the New York Times, Steyer referenced Republican senator Bob Corker’s recent claim that Trump’s advisers have to prevent him from taking destructive actions on a regular basis, and that the president’s impulsiveness could spark an unnecessary world war. Steyer further argued that Trump’s ties to Russia, and his shameless use of the presidency to promote his business interests, would also constitute grounds for removing him from office.

From one angle, Steyer’s position looks eminently rational. In recent months, the president has repeatedly issued tacit threats of a preemptive military strike and/or nuclear attack against Kim Jong-un’s regime in North Korea. In his recent interview with the Times this week, Corker said that these threats did not represent some deliberate “good cop, bad cop” routine, but were merely the impulsive ravings of a man who sees the presidency as “a reality show.” The senator went on to say that most of his Senate Republican colleagues share his assessment that Trump’s comportment puts the United States and world in great danger.

So: A man who is regarded as dangerously impulsive by people who spend a lot of time around him — and who have an enormous political incentive to view his behavior in the most generous possible light — currently has the authority to launch roughly 4,000 nuclear warheads, whenever he sees fit.

Is asking Democrats to promise that they will put an end to the situation, should they have the power to do so, really too much to ask? Shouldn’t anyone, regardless of party, find it unacceptable that an irrational actor has control of America’s nuclear arsenal?

And yet, from another angle, Steyer’s request seems bizarre. Democrats can’t impeach Trump without the support of two-thirds of the Senate. It is difficult to imagine the party laying claim to any more than 51 Senate votes in 2019 — and even that figure would require tremendous good fortune. If the Trump presidency ends in impeachment, it won’t be because Democratic lawmakers feel compelled to honor a pledge that they made to Tom Steyer, but because something so calamitous and/or criminal has occurred, a critical mass of congressional Republicans decide it is in their political interest to evict the mogul from 1600 Pennsylvania Avenue.

Given this reality, why put pressure on Democrats to come out in favor of impeachment, when the party is defending a slew of Senate seats in states where Trump remains popular?

One answer: Steyer’s letter isn’t primarily intended to lay out his conditions for supporting Democratic candidates, but rather, to lay down the foundation of his own Senate candidacy.

Steyer is reportedly considering a primary challenge against California Democrat Dianne Feinstein. Earlier this year, the octogenarian senator attracted the ire of a progressive crowd in San Francisco when she said of Trump, “The question is whether he can learn and change. If so, I believe he can be a good president.”

In his letter, Steyer wrote, “It is clear for all to see that there is zero reason to believe ‘he can be a good president.’”

A recent poll from the Public Religion Research Institute found that roughly seven in ten Democrats believe Trump deserves to be impeached.