IT’S NOT HARD TO think of a historical precedent for President Donald Trump’s attempts to trade military assistance to the Ukrainian government for actionable dirt on his chief political rival. The pathetic desperation of the crime itself, the bungling attempt at a cover-up, the incriminating transcript—“it really is stupid Watergate,” one Democrat told the Washington Post in September. The similarities to the scandal that forced Richard Nixon from office in 1974 extend to the people talking about it. An attorney on Nixon’s House impeachment committee, Bill Weld, is running for president. John Dean, Nixon’s White House counsel, and Carl Bernstein, who helped break the scandal, are CNN contributors. A Nixon dirty trickster, Roger Stone, recently went on trial for doing more of the same for Trump. And of course there’s…