Today's Democrats have grown up in the Saul Alinsky tradition, and on Thursday they proved it with a partisan vote to break the Senate filibuster rule for confirming judges and executive-branch nominees. The new rules will empower the party's liberals for as long as they control the White House and Senate, but they will also set a precedent for conservatives to exploit in the future.

Majority Leader Harry Reid broke a GOP filibuster of a judicial nominee on a 52-48 vote. He was prodded by the Democratic Senate classes of 2006-2012,...