Americans remain in broad agreement that Iran cannot be allowed to have nuclear weapons, with 78% taking that stand in the latest IBD/TIPP Poll vs. 77% the last time we posed the question in September 2006. However, unlike in '06, 52% now believe the U.S. should take military action to stop Iran from building nuclear weapons if diplomacy and economic sanctions fail. Two and a half years ago, when we asked if military action should be taken to stop Iran's uranium-enrichment activities, only 39% said yes. An even larger percentage are comfortable with Israel taking such action.