As votes in a few places are still being counted, the battle to fill Justice Antonin Scalia’s empty seat on the Supreme Court is already taking shape. Speaking on MSNBC last night and again this afternoon on WBUR’s “Here & Now” (NPR), Oregon Senator Jeff Merkley, a member of the important Senate Democratic Caucus, set forth what is likely to be a main line of argument going forward for Senate Democrats.

In a nutshell, given the failure of Senate Republicans to hold hearings on President Obama’s nominee, Judge Merrick Garland, the seat “is being stolen,” rendering anyone that President Trump might put forward “illegitimate.” As Merkley put it last night:

The seat that’s sitting empty is being stolen. It’s being stolen from the Obama administration and from the construct of our Constitution, and it’s being delivered to an administration that has no right to fill it. And we have to understand that this is about the Koch Brothers cartel working with the Republican majority to say that they want to basically pack the Court. ... There’s no legitimacy to a Supreme Court justice in a seat that’s being stolen from one administration and handed to another. We need to do everything we possibly can to block it. ... This is a theft being delivered to the Koch Brothers, and the Koch Brothers are not interested in We the People. It’s turning the Constitution on its head. This is government by and for the most powerful. It locks in Citizens United, which is completely against the mother principle that Jefferson laid out for an equal voice for citizens, and this is going to corrupt our political system in a way never envisioned or intended by our Constitution for a generation to come.

Asked if he would keep that seat open for as long as Democrats could, even if it took the entire duration of a term and keep a 4-4 Court, Merkley answered that first he would “call upon the majority leader that Merrick Garland gets a legitimate shot at a vote here in the lame duck, and then the Trump administration, if they want to see partnership and cooperation, if he puts forward a nominee it should be Merrick Garland.”

Doubling down on those points on NPR this afternoon, Merkley charged that “for the first time in history the Republican leadership failed to fulfill their responsibilities” and this “delegitimizes any nominee that Trump might put forward”—adding that “there’s still time to salvage this,” but “we’re facing a real problem ... in terms of legitimacy of whoever Trump might put forward. So we really have a deep corruption that is occurring through this stolen Supreme Court seat.” He concluded that “absolutely,” he would filibuster a nominee, adding that “we changed the application of the rules back in 2013. We left in place the filibuster on the Supreme Court.”

The “we” Merkley references was not the Senate as a whole, of course, but Senate Democrats, led by Harry Reid, who exercised the so-called nuclear option in order to “pack” the appellate courts with Obama nominees unacceptable to the Senate Republican minority. Doubtless, Reid and company wanted to keep the filibuster in place for Supreme Court nominations just in case they lost the Senate, which happened only a year later. But in the process, they lost the principle, even as the appellate courts they filled were upholding Obama’s rule by executive diktat.

Turning to Merkley’s main line of argument, however, the idea that the empty Scalia seat is being “stolen,” much less that it is being “handed” to a succeeding administration, as if it were some entitlement, simply boggles the mind. The Constitution is clear: The president nominates; the Senate advises and consents—or not. Given that the Senate has no duty to fill the seat, especially in an election year when primary voting was already underway when the vacancy arose, the seat could hardly be “stolen.” If the Senate fails to act, it simply falls to the Senate in the next Congress to take up the matter. This is quintessentially a political matter, plain and simple.

Nor does the Senate’s failure to act on one administration’s nominee in any way “delegitimize” its confirmation of a subsequent administration’s nominee. One has nothing to do with the other. Moreover, the filibuster is itself a political construct, not a constitutional imperative, and it has changed over the years. Having played with fire, Democrats have no ground for complaint if they should get burned down the road.

And it isn’t as if Senate Democrats are coming to these issues with clean hands. For nearly two years they sat on President George W. Bush’s first nine Republican appellate court nominations, holding no hearings at all for such legal luminaries as Michael McConnell, John Roberts, and Miguel Estrada. Only when the Senate changed hands did several of those nominations go forward. That’s politics—as provided for in the Constitution.