The relentlessly partisan Supreme Court confirmation process seemed to take a welcome bipartisan turn on Friday night when, in a dramatic reversal on the part of Jeff Flake, the Senate Judiciary Committee announced that it would ask the F.B.I. to reopen the background investigation into Judge Brett M. Kavanaugh. But by Sunday the Democrats were dismissing the investigation as a farce — and rightly so.

Thanks to the White House and Senate Republicans, not only is the F.B.I. limited to a weeklong investigation — a constraint the former F.B.I. director James Comey called “idiotic” in these pages — but, far more important, the bureau is seriously limited in terms of who it is allowed to interview.

President Trump tweeted on Sunday that he wants the F.B.I. to interview whoever “they deem appropriate.” But so far his tweet is the only indication that this is true.

Indeed, the Times has reported that Senate Republicans identified a list of just four witnesses: Mark Judge and P.J. Smyth, high school friends of Judge Kavanaugh’s; Leland Keyser, a high school friend of one of Christine Blasey Ford, who has accused Judge Kavanaugh of sexual misconduct; and Deborah Ramirez, another of the judge’s accusers. The Wall Street Journal, citing a “person familiar with the FBI’s thinking” reported that the bureau planned to stick to the people and topics directed from the White House unless the White House changes its mind.