Is Obama's proposed "nuclear umbrella" over Israel preferable to a preemptive strike on Iran...?

It's interesting . . . it's very similar to what Hillary proposed during the primaries . . . I think if this is going to work he needs to expand the countries under the umbrella to include all of our allies in the middle east . . . because if Iran does get a nuclear weapon, Israel will not be the only country looking to up the ante . . . Furthermore, it would be foolish for Israel to take this deal unless every major western power agreed . . . not just the U.S.