Lee Smith: How a former Iranian official and a U.S. foreign-policy guru are shifting Washington's stance toward regime change in Tehran - '...if the balance of threats from above (Israel) and below (the Iranian street) is not managed deftly, the Obama administration will find its assets are at cross-purposes. The bomb is a regime-saver, for there are few Iranians who do not believe that the proud and ancient Persian civilization merits the badge of technological prowess that a nuclear program represents. The easiest way for the Iranian regime to restore its battered credibility with its own people may be to ignore external pressure and work even harder to develop a bomb. By removing the threat of an Israeli attack, Obama gives Iran the time to acquire the bomb and with it the credentials to corral its domestic adversaries and cement its aggressive position at home and abroad.'