During O. J. Simpson’s trial for murder, his lawyers needed to throw the blame on someone besides their client. They settled on a vague story about drug dealers somehow tied to a close friend of his wife, Nicole Brown Simpson. The defense never even tried to explain why these malefactors “would have wanted to kill Nicole Brown Simpson (much less Ron Goldman),” Jeffrey Toobin wrote in his book about the trial. “That wasn’t the point of the defense strategy.” All the defense had to do was muddy the proverbial waters and gesture at an alternative theory of the crime.

The behavior of Republicans in Congress who are ostensibly investigating Russia’s interference in the 2016 election makes sense if you imagine them acting like Simpson’s lawyers. Though pretending to examine a crime against America, they are instead working to cover one up. To do so, they are spinning wild alternative scenarios with just enough surface plausibility to persuade the easily persuadable.

Because Republicans don’t have to prove their alternative theory, you rarely see it fully elaborated. But it goes something like this: Hillary Clinton’s campaign hired Fusion GPS to gather anti-Trump misinformation from Russia. Fusion GPS, working with the retired British spy Christopher Steele, then delivered the Russian smears to the F.B.I., which was determined to thwart Trump. So if anyone was guilty of collusion with Russia in the 2016 election, it was Clinton and her allies.

On Tuesday, Senator Sheldon Whitehouse, Democrat of Rhode Island, gave a speech on the Senate floor about all the rabbit holes into which Republicans have tried to divert the Russia investigation. His Republican colleagues, he said, “have been repeating, in chorus with the White House and conservative media, the disproven claim that the Russians somehow commissioned the Steele dossier, or that Steele somehow got suckered by the Russians, or that some deep-state F.B.I. set up the whole thing to pressure Trump.”