A handful of Republican state senators in Florida bucked G.O.P. leaders last week to help Democrats block a brazenly partisan court-packing plan from gaining a place on next year’s ballot.

Championed by the state’s Republican House speaker, Dean Cannon, and approved by his chamber, the plan called for expanding the Supreme Court from seven to 10 justices, and splitting the bench into two separate five-member divisions for criminal and civil cases. The proposed amendment to Florida’s Constitution would have given the state’s conservative Republican governor, Rick Scott, three new seats to fill on the civil side.

Backers of this radical overhaul offered specious arguments about court efficiency and a nonexistent backlog problem, which were effectively debunked by an impressive array of state and national bar leaders, civic groups, and former state justices and senior judges.

The apparent aim was to retaliate against the court for tossing out defective ballot initiatives last year that had been approved by the Republican Legislature, and to get next year’s round of redistricting cases before a new civil division dominated by judges named by Mr. Scott. Unfortunately, while the court-packing was rejected, other mischievous changes were approved for the ballot, including a provision to allow the Legislature to repeal procedural rules set by the court. And the court-packing fight may not be over. The Legislature has allotted $400,000 for a study of court operations that threatens to revive the issue next year. Bolstered by last week’s victory, opponents of political meddling with the courts need to be ready.