Joe Manchin III could quite reasonably say he is the reason Democrats have a majority in the Senate and President Biden has any hope of turning his policy agenda into law. The West Virginia senator is just about the only Democrat who would have a chance to win in a state Biden lost by 39 points. Had he retired last year to run for governor, his seat would have undoubtedly gone to a Republican and Mitch McConnell would still be majority leader.

So now Manchin sits at the Senate’s fulcrum, its most conservative Democrat and the 50th vote his party will always need to pass anything. Which is why the future of the country quite literally depends on how Manchin uses his newfound power.

In theory, Manchin should be on board with much of Biden’s agenda, especially the parts focused on promoting a more aggressive government provision of services and combating inequality. West Virginia is by some measures the poorest state in the country, and Manchin can be the one who brings all kinds of benefits to his constituents.

Unfortunately, his political brand is built on being the Democrat who tells Democrats they’ve gone too far. His moderation is built on both substance and his willingness to tell his own party, “Not today, libruls.”

So how do they manage him? Part of it will have to be old-fashioned butt-kissing, inviting him to the Oval Office and seeking his wise counsel on everything. The need was highlighted recently when he grew angry that Vice President Harris gave an interview to a West Virginia TV station about the administration’s proposed covid relief bill without informing him first, as though no one is allowed to venture to the state, even via Skype, without his approval.

They’re also going to have to work on him when it comes to the filibuster — which is ironic, given how much more power he’d have if it were eliminated.

Manchin regularly says publicly not only that he will never vote to eliminate the filibuster but also that he believes it can force bipartisan cooperation. Which makes sense as long as you know nothing about how the Senate actually works today.

You might think that if the votes of multiple opposition senators are needed to pass anything, that would force the ruling party to reach out, compromise and fashion solutions everyone can live with. But in a polarized age where the parties have starkly different agendas, all it means is that it’s impossible to pass anything, because the minority party exercises a veto over everything the majority party wants to do.

That ability to thwart the majority party is so powerful that the minority can’t help but use it. Which is why, as Adam Jentleson points out, it’s the lack of a filibuster that will promote bipartisanship: Knowing that the majority can pass something with or without them, the minority will move early to enter negotiations and shape legislation more to its liking. The result can be bipartisan bills.

As for Manchin, with the filibuster in place, he has no power over anything but reconciliation bills: If Republicans are going to kill every bill anyway, the guy with the 50th vote is just as unimportant as the guy with the first or the 10th or the 20th.

But if you can pass bills with 50 votes, then the 50th vote has all the power. He can demand anything he wants, whether it’s goodies for his home state or just bills that reflect his particular priorities and preferences.

While in theory any Democrat has that power, in practice most of them don’t, for the same reason that the Progressive Caucus doesn’t have the influence among Democrats that the Freedom Caucus has among Republicans: In the end, the liberals won’t vote against legislation that helps people, so their threats to blow up worthwhile bills aren’t credible. The Freedom Caucus can make that threat because they’re legislative nihilists.

And Manchin can make that threat because he really is a centrist — and one whose political survival depends on him separating himself from other Democrats.

But that’s not always the case. Manchin might listen to current West Virginia Gov. Jim Justice (himself a former Democrat who switched to the GOP), who urged Congress to go big on covid relief, because the risk of doing too much is far smaller than the risk of doing too little.

“If we actually throw away some money right now, so what?” Justice said on CNN. “We have really got to move and get people taken care of.”

Fortunately for Manchin, the public cares much more about whether Congress helps them than whether they did so in a bipartisan way. And guess what: If Manchin uses this occasion to show Republicans in Congress that when the chips are down he’ll vote with his party, that will make them more eager to get in on the action and negotiate, which will mean that Manchin created bipartisanship. Everybody wins!

One hopes Manchin will see that it’s more in his interest — and the interests of Americans — to stick with Democrats most of the time. And perhaps they can come up with some sort of partial elimination of the filibuster, so that bills can move and he can still say he didn’t get rid of it entirely. But no matter what happens, we’re going to spend a lot of time asking what Manchin wants and whether he’s happy. Let’s hope he doesn’t stand in the way of too much progress.

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