Extension of the Nuclear Umbrella

Beginning in the Presidential primaries this year Hillary Clinton floated the idea of creating a nuclear umbrella for Israel (and perhaps other countries in the Middle East) to help deter an Iranian aggression. Ha’aretz recently broke a story citing an unnamed source close to the Obama Administration who claims that Obama will, in fact offer this nuclear umbrella to Israel. Doug Bandow recently wrote an article  for the National Interest in which he is highly critical of the idea of extending the nuclear umbrella to Israel or others. After raising a host of arguments against extending the umbrella he concludes,

Ever since the cold war ended, U.S. foreign policy has presumed Washington’s right to meddle, promiscuously intervening in conflicts with little or no relevance to American security. Opening a nuclear umbrella over Israel and other Middle Eastern states would be more of the same. But it’s time for change that we can believe in on foreign as well as domestic issues. It’s time for Washington to begin avoiding rather than joining conflicts around the globe.

Is there merit to Clinton’s proposal or does Bandow have it right on? Can the nuclear umbrella help prevent aggression and stop states from going nuclear, or is it a risky idea, lacking credibility?