Mr. Romney and his advisers are making the mistake that John Kerry made against George W. Bush in 2004—believing that voters are so unhappy with the incumbent that all Mr. Romney has to do is present himself as a safe alternative. Mr. Romney seems to think it’s enough to run on his biography as a businessman.

It won’t be enough—unless the economy goes into another recession, which no one should want in any case. The Republican nominee will have to make a sustained and specific case that Mr. Obama’s policies made the recovery weaker than it should have been (stimulus, health care), squandered resources on political boondoggles (Solyndra), and how and why GOP policies will do better. Mr. Romney’s 59 economic proposals are fine but forgettable little ideas. He needs a big idea.

In the wake of his victory, Mr. Gingrich has his own challenge because he has always been at his worst when he is on top. The Georgian’s main vulnerability isn’t his failed marriages, as South Carolina proved. It is his penchant for over-the-top statements and sudden shifts of strategy or policy based on personal whim. In South Carolina, for example, he began to rise when he muted his misguided attacks on Bain Capital and focused on other issues…

As for the GOP establishment, such as it still is, Mr. Gingrich’s re-emergence is likely to cause a panic attack. They don’t believe he is electable. Our advice would be to relax and let the voters decide. If Mr. Romney can’t marshal the wit and nerve to defeat the speaker, then he isn’t likely to defeat Mr. Obama.