Zombies have long ruled the Republican Party. The good news is that they may finally be losing their grip — although they may still return and resume eating conservative brains. The bad news is that even if zombies are in retreat, vampires are taking their place.

What are these zombies of which I speak? Among wonks, the term refers to policy ideas that should have been abandoned long ago in the face of evidence and experience, but just keep shambling along.

The right’s zombie-in-chief is the insistence that low taxes on the rich are the key to prosperity. This doctrine should have died when Bill Clinton’s tax hike failed to cause the predicted recession and was followed instead by an economic boom. It should have died again when George W. Bush’s tax cuts were followed by lackluster growth, then a crash. And it should have died yet again in the aftermath of the 2013 Obama tax hike — partly expiration of some Bush tax cuts, partly new taxes to pay for Obamacare — when the economy continued jogging along, adding 200,000 jobs a month.

Despite the consistent wrongness of their predictions, however, tax-cut fanatics just kept gaining influence in the G.O.P. — until the disaster in Kansas, where Gov. Sam Brownback promised that deep tax cuts would yield an economic miracle. What the state got instead was weak growth and a fiscal crisis, finally pushing even Republicans to vote for tax hikes, overruling Brownback’s veto.