Democratic presidential front-runner Hillary Clinton will promise on Wednesday to strictly enforce the nuclear deal with Iran and curb the Islamic Republic's regional ambitions if she wins the November 2016 election.In a speech to a Washington think tank, the former secretary of state will reiterate her support for the accord but caution that the United States needs to take an approach of distrust and verify toward Iran, a senior Clinton campaign official said."I support this deal. I support it as part of a larger strategy toward Iran," Clinton will tell the Brookings Institution, according to excerpts of her prepared remarks.But it is not enough just to back the agreement, she will add."We have to say 'Yes - and.' 'Yes, and we will enforce it with vigor and vigilance,'" Clinton is to say.