As majority leader, Mr. Reid has shamelessly manipulated the Senate to Democratic advantage. He blocked an up-or-down vote on the Keystone XL pipeline and on repeal of ObamaCare’s medical-devices tax. He split the American Jobs Act, which Mr. Obama had touted in a speech to Congress, into individual parts. To pay for it, Mr. Reid added tax increases, including the Buffett tax with its 30% minimum income-tax rate on millionaires. This insured that Republican opposition would kill the bill and thus Democrats could trumpet their favorite theme: Republicans blocked legislation to save their rich friends from higher taxes.

When bipartisan curbs on the Environmental Protection Agency’s anti-coal regulations were under consideration in June, Mr. Reid shut down the process in committee. He held what was called an “all-night filibuster” on the Senate floor. It was pure issue advocacy without a bill to vote on.

The Reid strategy has made it impossible for Republicans to point to bipartisan victories in the Senate. But this has backfired against Democrats, especially those seeking re-election in red states. In sidelining popular bills, Mr. Reid has given Democrats no achievements to brag about. In six years, Mr. Begich failed to get a vote on a single amendment he proposed.