Will Democrats Really Nuke the Filibuster—and What Happens If They Do?

President Joe Biden's agenda has stalled on Capitol Hill halfway through his first 100 days in office. Biden's supporters fear that if Democrats in Congress don't act soon, they will have squandered their best opportunity to pass such policy priorities as a climate action bill, election legislation, and immigration reform. Supporters are especially frustrated with Senate Democrats for allowing their chamber's Republicans to filibuster bills passed by the Democratic-controlled House.

The Senate, unlike the House, permits a minority of its members to block bills supported by a majority. Specifically, Rule...