What the optimists are missing is that the House remains the linchpin of all their future ambitions. A Republican presidency will mean little with Speaker Nancy Pelosi redux. Mr. Obama may well win re-election. What leverage will a Republican-run Senate have in the face of that, and a Democratic House? Or consider the possibility that Republicans botch both the Oval Office and the Senate.

True, the National Republican Congressional Committee (NRCC), under Texas Rep. Pete Sessions, is aware of the challenge and is energetically fund-raising and recruiting. True, the party is already coaching its newer members about the rigors of re-election. And true, John Boehner and Eric Cantor are going all out to collect money for their members. The speaker alone raised some $46 million in 2011—nearly double his take for the entire last election cycle.

What Messrs. Boehner and Cantor know is that they’ll need all this, and more. The House is no sure thing.