Congress is in danger of taking that most cursed of American political disagreements, the debate over illegal immigration, and dragging it farther toward insanity.

Bills are being rushed to the floor in the House and Senate in response to a woman’s senseless killing in San Francisco by an unauthorized immigrant with a long criminal record. That single crime has energized hard-line Republican lawmakers who have long peddled the false argument that all illegal immigrants are a criminal menace, and that the best way to erase their threat is by new layers of inflexible policing.

On Thursday afternoon the House passed the first of these bills, to punish state and local governments that limit cooperation with immigration enforcement and that forbid their officers to question the people they encounter about their immigration status. It would deny places with such “sanctuary” policies funding from the Homeland Security and Justice Departments for public-safety programs, essentially bleeding them of money to fight crime — in the name of fighting crime. Another measure pending in the House, “Kate’s Law,” named for the San Francisco victim, Kathryn Steinle, would impose mandatory five-year minimum prison sentences for deportees caught re-entering the country.

In the Senate, Charles Grassley of Iowa has offered a bill that combines the sanctuary-city and “Kate’s Law” provisions. Rand Paul of Kentucky and David Vitter of Louisiana have their own sanctuary-city bills, and Ted Cruz of Texas has jumped on the “Kate’s Law” bandwagon.