Former national security adviser John Bolton, lobbing a hand grenade into the midst of the impeachment proceedings, announced Monday that he is prepared — if subpoenaed by the Senate — to testify after all. Perhaps this is the ultimate in cynical maneuvers: a canny Washington player making an offer that he knows Senate Majority Leader Mitch McConnell (R-Ky.) can afford to refuse.

No doubt that is McConnell’s instinct. The majority leader is not interested in getting to the truth of President Trump’s dealings with Ukraine and, therefore, has no desire to hear the kind of firsthand testimony that a former national security adviser could offer about his dealings with the president and his inner circle — what Bolton characterized as a “drug deal” being cooked up by acting White House chief of Staff Mick Mulvaney and Gordon Sondland, the ambassador to the European Union, in former National Security Council aide Fiona Hill’s memorable retelling.

But are McConnell’s fellow Republicans so heedless of their constitutional duty, so committed to a see-no-evil, hear-no-evil approach to Trump, that they would fail to take up the opportunity to hear from Bolton? After all, it would only take four of them to stand up — to McConnell, to Trump, to the GOP base — to amass the votes necessary to subpoena Bolton.

That could have been done absent Bolton’s statement, of course. But the significance of his announcement is to signal that calling him to testify would not be a fruitless maneuver, destined to be tied up in months of litigation. Instead, Bolton — or so he said — stands ready to talk. Significantly, and Bolton is a careful lawyer, he did not suggest that his willingness to answer questions would be limited in any way by concerns over executive privilege.

The road to this moment has been twisting, and Bolton’s moves and motives obscure. Is this offer a bit of carefully calibrated payback for a president who fired him by peremptory tweet? “I informed John Bolton last night that his services are no longer needed at the White House,” Trump wrote. “I disagreed strongly with many of his suggestions, as did others in the Administration, and therefore I asked John for his resignation, which was given to me this morning.” Bolton, disputing Trump, said he offered the resignation without being asked. If revenge is a dish best served cold, Bolton has now waited nearly four months — and he can frame his appearance as a reluctant willingness to perform his constitutional duty.

Bolton has been playing a cagey legal game throughout the impeachment proceedings — seeming to want to tell his story but not to appear to be doing so voluntarily. In response to a House subpoena, Bolton’s former deputy, Charles Kupperman, went to court to ask for instruction about whether he should comply with the subpoena or the president’s order not to testify. Bolton, represented by the same lawyer, said he would abide by the ruling in that case. But the House withdrew its subpoena, and the judge last month dismissed the case as moot.

“It now falls to the Senate to fulfill its constitutional obligation to try impeachments, and it does not appear possible that a final judicial resolution of the still-unanswered constitutional questions can be obtained before the Senate acts,” Bolton said in a statement posted on his political action committee’s website. “Accordingly, since my testimony is once again at issue, I have had to resolve the serious competing issues as best I could, based on careful consideration and study. I have concluded that, if the Senate issues a subpoena for my testimony, I am prepared to testify.”

If. Why would any senator charged with the grave responsibility of trying the president on articles of impeachment not want to hear Bolton’s account? How could any senator justify refusing to hear from someone so central to Trump’s handling of Ukraine? McConnell’s ability to keep his caucus under control should not be underestimated — he orchestrated the successful blockade of Supreme Court nominee Merrick Garland — but it is also not complete. Under pressure, albeit with a thinner majority, he acceded to an FBI investigation, however inadequate, of then-Supreme Court nominee Brett M. Kavanaugh.

Republican senators with a modicum of self-respect need to ask themselves: Did they really work this hard, did they really go to Washington, just to cover for Trump? Are there four members who can handle the truth?

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