If you're just joining us after a brief holiday in a local cave, the blockbuster news this weekend has been not just that US intelligence believes Russian state-sponsored hackers were behind attacks on institutions of the Democratic Party and on individual state elections infrastructure, but that those acts were carried out with the explicit Russian goal of electing Donald Trump over Hillary Clinton.

But even that was widely suspected already. What we didn't know is that after the hacking attacks were identified, an alarmed Barack Obama summoned top House and Senate leaders to hear the intelligence summaries and take protective measures:

Specifically, the White House wanted congressional leaders to sign off on a bipartisan statement urging state and local officials to take federal help in protecting their voting-registration and balloting machines from Russian cyber-intrusions.

But the president couldn't get that bipartisan agreement. And the reason he couldn't get it was because Sen. Mitch McConnell refused to give it to him. Then he did more:

[Intelligence officials] made a case for a united, bipartisan front in response to what one official described as “the threat posed by unprecedented meddling by a foreign power in our election process.” The Democratic leaders in the room unanimously agreed on the need to take the threat seriously. Republicans, however, were divided, with at least two GOP lawmakers reluctant to accede to the White House requests. According to several officials, McConnell raised doubts about the underlying intelligence and made clear to the administration that he would consider any effort by the White House to challenge the Russians publicly an act of partisan politics.

That goes beyond refusing to issue a statement asking states to beef up their election security in the face of a wave of Russian hacking. This was a direct assertion that if the sitting president publicized the Russian attacks or attempted to retaliate or challenge Russia over them, the Senate Majority Leader would go on television and declare that it was the sitting president, not Russia, who was attempting to meddle in the election.

That may be consistent behavior from McConnell, who has so devoted himself to crippling Obama as president that he has done everything from foiling attempts to revive the economy to inventing a new rule declaring that the first black American president isn't allowed to appoint new Supreme Court justices for the entire last year of his term. But it's still shocking and—hopefully—unprecedented. This was Mitch McConnell playing the precise role that Donald Trump himself would play later—declaring that the underlying intelligence itself was false, and that therefore any action the intelligence community or the White House took would be "partisan."

He saw the evidence that Russia was behind both attacks on Democratic Party infrastructure and state elections offices, and the response was to warn his president not to take public action based on those foreign attacks before the election—even as those attacks continued.

Sen. McConnell needs to explain himself. So far, as usual, he has remained silent. But what it very much looks like from here is he became a man so obsessed to blocking Obama and boosting his Republican agenda that he not only dismissed intelligence reports of ongoing hacks of America's election process, but blocked attempts to react to them by threatening to himself sabotage the effort.

It's not an ask. Sen. McConnell needs to come forward and explain himself, and he had better think long and hard about what he's going to say.