There’s another big difference between Nixon and Trump. Nixon understood the political risk he was taking, and balanced it against his foreign policy objectives. According to the Bob Woodward and Carl Bernstein book “The Final Days,” Nixon “knew that firing Cox would invite a move to impeach.” But he believed letting Cox publicly demand the tapes in defiance of a presidential order would make him look weak in the eyes of the Soviet leader Leonid Brezhnev. As Nixon told his unimpressed attorney general, “Brezhnev wouldn’t understand if I didn’t fire Cox after all this.”

Trump, on the other hand, doesn’t seem to understand or care about the political risk. He fired Jim Comey, according to White House aides, believing Democrats would applaud. Whether or not that was true, he knows by now that another self-serving firing would not juice his poll numbers—and would galvanize Democrats even more. If Trump rids himself of Mueller, it wouldn’t be because he believes the need to exude strength internationally outweighs the added risk of impeachment. It would be a brazen attempt to shut down the investigation and prevent impeachment.

The cold truth is that it might work. So far, the indications are that House Republicans would stand by Trump and not consider impeachment, and that they would be backed up by most Republican voters.