Former national security adviser John Bolton just shocked the political world by putting out a statement claiming that he is prepared to testify at President Trump’s impeachment trial if the Senate subpoenas him:

I have concluded that, if the Senate issues a subpoena for my testimony, I am prepared to testify.

Bolton had refused to testify during the House impeachment inquiry, saying he would be guided by the courts’ decision in a case involving another top aide close to Bolton who had been subpoenaed but then refused to testify. House Democrats withdrew that subpoena, because it would have taken months to legally resolve, and impeached Trump based on the extraordinary amount of damning evidence they succeeded in collecting without him.

This left Bolton dangling out there with no remaining excuse not to tell the world what he knows, and he apparently has now decided he’s willing to do so.

Before considering his motives in doing this and whether it’s likely to happen, let’s recall what Bolton might know. Witnesses testified that Bolton was deeply disturbed when Trump’s ringleaders made it clear that a White House meeting between Trump and Ukrainian President Volodymyr Zelensky was conditioned on getting Ukraine to announce the investigations Trump was demanding. Bolton called this a “drug deal.”

Bolton also privately urged the president to release the withheld military aid to Ukraine, according to the New York Times. And The Post reported back when Bolton was resisting testifying that he was “aghast” at the freezing of the aid, and that if a court directed him to do so, he’d testify directly to his personal conversations with Trump over these matters.

Numerous theories are floating around about why Bolton is suddenly willing to talk. One is that he’s trying to drum up publicity for his forthcoming book. Another is that he’s really psyched that Trump is escalating against Iran, making the war Bolton has craved for so long more likely, and he now wants to help Trump by cleaning up his “drug deal” comment. Still another is that he’s looking to help Trump to secure his own future in the Republican Party.

But these theories miss the key point, which is that Senate Republicans now have to decide whether they’re willing to take Bolton up on his offer and allow him to testify.

For one thing, as The Post’s Jennifer Rubin points out, this means House Speaker Nancy Pelosi (D-Calif.) has just been given new leverage to keep insisting that Senate Majority Leader Mitch McConnell (R-Ky.) agree to a real trial, including witnesses such as Bolton, while she delays in sending over the articles of impeachment.

I would add that this also badly undercuts one of the GOP’s dumbest talking points: That the only reason House Democrats haven’t sent over the articles is because their case is weak. By saying he’s willing to testify, Bolton has suddenly made the choice that Senate Republicans must face into something that’s very real: Either they accept Bolton’s offer, or they decline it.

In other words, either their choice does result in him testifying, as he has volunteered to do, or it results in him not being allowed to testify, despite having explicitly volunteered to do so.

No matter how much Trump’s defenders try to spin and lie this away, the basic dynamic is as follows: Senate Republicans cannot allow testimony from the witnesses Democrats have demanded — which include Bolton, acting White House chief of staff Mick Mulvaney, and two senior White House budget officials — precisely because they have the most direct knowledge of Trump’s corrupt extortion plot.

In particular, they were deeply involved in Trump’s freezing of the aid, which the president’s defenders still deny he withheld for the corrupt purpose of pressuring Ukraine, even though ringleader Gordon Sondland, the U.S. ambassador to the European Union who was acting at Trump’s direction throughout, directly conveyed to Ukraine that the aid was contingent on doing Trump’s dirty political deeds. Indeed, this is exactly why Trump wouldn’t allow these very same people to testify during the House impeachment inquiry.

What’s more, new revelations about the depths of concern over the illegality of the aid freeze inside the administration have confirmed another aspect of the basic dynamic here: If Senate Republicans do succeed in blocking witnesses at Trump’s trial, more will keep coming out, showing in retrospect exactly what Senate Republicans were so eager to cover up all along.

That could happen with Bolton as well. If Senate Republicans refuse his testimony, what happens if he shares what he knows at some future date?

Yet even despite those risks, they may have to refuse his testimony, because allowing it constitutes an even worse risk. If that happens, it will now look all the more damning.

If nothing else, Bolton’s willingness to testify, by challenging Senate Republicans to either allow a full reckoning or to even more shamelessly prevent one, further underscores the absurdity and sheer untenability of their position.

Read more: