The Wall Street Journal thinks so:
As for the potential threat of military strikes to assist diplomacy, Defense Secretary Robert Gates has made his doubts about their efficacy very public. The President's two-week public attempt to humiliate Benjamin Netanyahu has also considerably lessened the perceived likelihood of an Israeli strike on Iran, thereby further diminishing whatever momentum remains for strong sanctions.
All of these actions suggest to us that Mr. Obama has concluded that a nuclear Iran is inevitable, even if he can't or won't admit it publicly. Last year Mrs. Clinton floated the idea of expanding the U.S. nuclear umbrella to the entire Middle East if Iran does get the bomb. She quickly backtracked, but many viewed that as an Obama-ian slip.
On the other hand, no one, IMHO, has made a convincing argument that a military strike could, in fact, work.