Democrats are grasping at straws to try to stop Republicans from replacing retiring Justice Anthony M. Kennedy on the Supreme Court with a more reliable conservative vote.

That's because, beyond misconstruing what Republicans said in 2016 about holding up Supreme Court nominees in an election year, Democrats don't have any procedural recourse to stop Senate Republicans from approving President Trump's pick.

Democrats can't hold up Supreme Court nominees by requiring that they get a 60-vote consensus. After a rules change last year that both parties had a hand in precipitating, a simple majority will do. And at least until the November elections, Republicans have a one-or-two-vote majority in the Senate (depending on Sen. John McCain's health and his ability to return from Arizona to vote).

But here's the most important thing to note: Constitutionally, the Senate can consider a president's Supreme Court nominee whenever it wants. That means senators can wait until after a presidential election, like Senate Republicans decided to do when Justice Antonin Scalia suddenly died in February 2016. Or they can do it right away, like Republicans now say they'll do for Kennedy's seat.

Russell Wheeler, a judicial expert with the Brookings Institution, told The Fix in 2016 that there's no rule or article in the Constitution stating otherwise.

The Constitution is actually pretty vague about the Senate's role in approving Supreme Court nominees. It just says the Senate will provide “Advice and Consent” to the president on these nominees, said Cornell Law professor Josh Chafetz.

There is no timeline nor guideline for how to hold confirmation proceedings. The Constitution doesn't even say how big the court needs to be. In 2016, some Senate Republicans argued that it would be all right if the court stayed at eight or fewer justices forever, as a way to justify holding off on considering President Barack Obama's pick, Merrick Garland. There have been as few as six justices and as many as 10 in U.S. history.

So can you argue  that Republicans are making overtly political decisions when they consider a president's Supreme Court pick? Absolutely. But that doesn't mean they are breaking the rules in doing it, as Democrats have tried to suggest.

There's some talk of two  Republican senators who support abortion rights opposing a Trump pick who wants to overturn a Supreme Court ruling legalizing abortion. One of those senators, Susan Collins of Maine, did tell reporters that she always looks “for judges who respect precedent.” But there's no actual evidence that Collins or Lisa Murkowski (R-Ala.) would buck their party on such a consequential vote . . . and a smart nominee will avoid commenting on how they'd rule on hypothetical cases, as Justice Neil M. Gorsuch did in his confirmation hearings last year.

It's possible that the reverse happens — that Senate Democrats up for reelection in states that Trump won in 2016 cross party lines to approve Trump's pick.

Procedurally, that would be the end of the line for Democrats. They're pretty much out of luck trying to stop a swing vote from being replaced by a more reliably conservative one, hardening the court's 5-4 rightward lean.

But while the Kennedy seat might be lost to Democrats, there's a very different angle that Democrats can take — and already are — to prevent a further conservative tilt of the Supreme Court under Trump's term: politics.

Here, the Senate and the 2020 presidential campaign collide. Democrats have a chance, albeit a small one, to take back control of the Senate in November. Republicans are planning to have filled Kennedy's vacancy by then.

Democrats are hoping that if they take control of the Senate, they can be a moderating influence on any other vacancies during the rest of Trump's tenure. Of the court's four liberal justices, two will be older than 80 by then — Justice Ruth Bader Ginsburg (85) and Justice Stephen G. Breyer, who turns 80 this summer.

It's not a coincidence that on Thursday, three Democratic senators who are thought to be running for president in 2020 have addressed supporters outside the Supreme Court.

The message to Democratic voters is clear: Democrats are at risk of losing their grip on the Supreme Court for a generation. So vote for Democrats to try to stop it.

It's an open question whether that strategy will work.

In national exit polls from 2016, Republicans were slightly more likely than Democrats to say appointments to the Supreme Court were the most important or an important factor in their vote.

But Democrats were only a few percentage points behind: Of the voters who ranked this as the most important or an important issue, 76 percent were Republicans and 68 percent Democrats.

Democrats' best hope now is that things are so dire for them that their base will make Supreme Court picks more of a  priority, even in a congressional election year where the president isn't on the ballot. After all, Republicans now have a chance to shape the highest court in the land in a more conservative mold, possibly for a generation.

Scott Clement contributed to this report.