This is dangerous. Not just because of damage it could do to our ideological struggle against jihadists, but because it corrodes the ties between citizens. Americans are afraid, and this validates their fears. It tells them, explicitly, that Muslim Americans are dangerous—a potential Fifth Column that needs monitoring, questioning, or worse. And for those prejudiced enough to do violence, it loosens the bonds that might keep them from acting on their fear and hatred.

President Obama has urged Americans to show tolerance, but Republicans won’t listen. Not only did he insult them, but this is a partisan issue and Republicans stand to gain. Why would they back down now?

Because we’re moving toward an ugly place. Because we shouldn’t indulge our worst impulses. Because this rhetoric puts actual lives at risk—since Paris, authorities have seen a surge in anti-Muslim threats and vandalism.

Republicans won’t listen to Obama on this score, but they might heed George W. Bush, who still holds sway with the party. He doesn’t need to say anything new or novel. He just needs to remind his party that there’s more to politics than winning—that some victories aren’t worth the cost to the country.