balancing optimism with credibility

 The formula for restoring national confidence — part good policy, part good politics, part good luck — can be hard to find. It eluded Herbert Hoover after the Crash of ’29, Lyndon B. Johnson after the Tet offensive, Jimmy Carter after the energy shock and George W. Bush after Iraq turned from quick victory to bloodyinsurgency.

“The hardest part of this is balancing optimism with credibility,” said Mr. Dallek. “Hoover’s ‘Happy days are here again’ wasn’t credible. Bush’s ‘Mission accomplished’ became a running joke. No one wants to make that mistake again.”