A once-obscure 1996 statute lets Congress kill a federal rule in an afternoon, bypassing the filibuster entirely. Only 20 of 461 attempts have become law since it took effect.

A 1996 law lets Congress erase agency rules with a simple vote, and this month it's aimed squarely at California's authority to write its own tailpipe standards.

The EPA transmitted four California vehicle and equipment emission waivers to Congress on Friday, arguing they qualify for fast-track repeal under the Congressional Review Act.