In the 1944 noir film “Gaslight,” a villain hides his crimes by convincing his innocent wife she’s insane, feeding her barely perceptible lies and altering small aspects of her environment until she doubts her own instincts and observations.

Senate Republicans are attempting the same scheme on their Democratic counterparts, trying to convince them and the rest of the world that if Republicans invoke what’s known as the nuclear option to confirm Judge Neil Gorsuch as a Supreme Court justice, it would be the Democrats who were responsible — not the Senate majority leader, Mitch McConnell, the man who would pull the trigger.

No one should fall for Republicans’ trickery. Democrats are right to embrace their principled opposition to Judge Gorsuch and remember that however Mr. McConnell chooses to respond, it will be his decision alone.

Going nuclear, or changing Senate rules to make a Supreme Court confirmation possible with a simple majority, would be a hugely disproportionate response to reasonable Democratic opposition and will expose Mr. McConnell’s much-ballyhooed “institutionalism” as the fraud it has always been.