Kirsten Gillibrand is running into problems from an unusual source: the Democratic donor class. Amanda Terkel reports at HuffPost that big-time donors are furious at her for saying that Bill Clinton should have resigned, and for pressuring Al Franken to quit the Senate after eight women accused him of groping. The enraged bourgeois include George Soros and, rather oddly, a number of wealthy women.

This probably seems bad to Gillibrand and her staff, but it's actually a golden opportunity for her — perhaps her best chance to date to solve her biggest political problem: the perception that she is a political weathervane with no clear principles, fatally compromised by Wall Street cash. These are enemies worth having.

On one level, it is pretty hilarious to see self-professed acolytes of Hillary Clinton — one of the all-time finger-in-the-wind triangulators of American political history — complain about politicians being "opportunistic." But that is just another example of the canting hypocrisy of the donor class. They furiously demand party unity when leftists criticize centrist Democrats, but should a leftist win a primary, they routinely refuse to endorse or even run third-party campaigns, thus risking throwing the election to the GOP. What they care about is keeping Their People in charge, even if that leaves the Democratic Party a smoking ruin.

So that raises the question of 2020 Democratic presidential politics. This is almost certainly going to break down along similar lines as the 2016 primary, with a left faction and a centrist faction — only with many more candidates. On the left, Bernie Sanders is by far the most credible candidate and the probable frontrunner, with a mile-long record of consistent principles. Elizabeth Warren doesn't have quite as good a record, but she is better on details, a bit younger, and a woman.

Centrists will probably include Mike "Big Gulp" Bloomberg, Joe "Student Debt" Biden, and perhaps another senator or two.

It's hard to judge which faction is going to come out on top. Clearly the left has the wind at their backs, with Sanders rolling up gargantuan margins among younger people in 2016 and generally posting the best favorability numbers of any working national politician. Now, it is hard to predict how a multiple-candidate race will play out, and if one faction is splintered while the other is united, they might easily win even without the majority of support (as Donald Trump showed in 2016). Still, if I had to bet, I would put money on Sanders or Warren.

Gillibrand seems to agree, as she has been trying to cement her left bona fides. She has endorsed Medicare for All, voted against almost all of Trump's nominees, and spoken out against Franken and Bill Clinton — as we've seen, infuriating the big money with the last one. But she has also tried to straddle the divide, endorsing the odious, incompetent, Republican-enabling troglodyte Andrew Cuomo in the New York governor's race, and thus infuriating the left.

This is poor strategy. Politicians often assume that cynical, duplicitous pandering — talking a big game on helping the average voter while making peace with corrupt machine bosses and handing out goodies to the rich — is the best way to achieve success. And in prosperous times, as Bill Clinton showed in the 1990s, that can be a winning strategy.

But in times of intense political polarization and extreme economic dysfunction, the path of political wisdom often lies not in trying to split the difference, but in picking a side and sticking to it. This is something Franklin Roosevelt understood very well. In the early New Deal he attempted to create a grand coalition including both business and labor, but when business turned on him, he decisively threw in his lot with the working class, pushing for union protections, anti-trust policy, Social Security, banking regulation, and eye-watering tax hikes on the rich (among many other things). He then made enormous political hay out of the ensuing capitalist outrage, railing against "government by organized money" and gleefully mocking wealthy Republicans. The Democratic rank and file followed his lead, and his record of enormous policy success led to sweeping political victories.

So for Gillibrand, there is no way she could match Sanders' consistent history. On the contrary, she will have to live down a record of immigration restriction, austerity, tobacco lobbying, and worst of all, Wall Street obedience. She has mostly gotten clear of the first problems, but not the last one.

One effective way to do that is to pick a lot of loud and noisy fights with the donor class and rich capitalists in general, especially in finance (as Sanders is constantly doing). Someone with her record of catering to Wall Street is going to have to signal credibly that she has changed her mind. And that means not just having some policy papers, but refusing corporate money and deliberately stoking fury among financiers. Basically, if Stephen Schwartzman doesn't compare her to Hitler, she's going to get outflanked by Sanders or Warren.

And anyway, the donors already dislike her — so there's hardly anything left to lose. Today is a populist, anti-establishment time. Being timid and trying to appease all sides is just going to alienate everyone.