Mitt Romney has triumphed in the Florida primary despite a campaign attacking his treatment of Holocaust survivors.
The former Massachusetts governor achieved 46 per cent of the vote, but Florida's winner-takes-all system means he has gathered 50 more delegates ahead of summer's Republican Convention.
It emerged during the voting that his rival Newt Gingrich was highlighting Mr Romney's s opposition to state-funded kosher provision in nursing homes, which he blocked as governor in 2003.
In an automated telephone call, paid for by the Gingrich campaign, Florida voters were told: "Holocaust survivors...for the first time were forced to eat non-kosher because Romney thought $5 was too much to pay for our grandparents to eat kosher.
"Tuesday, you can end Mitt Romney's hypocrisy on religious freedom."
But Mr Romney's decision eight years ago did not appear to have damaged him in the state, where 3.4 per cent of the population is Jewish.
Mr Gingrich, who beat Mr Romney in last month's South Carolina primary, came second with 32 per cent of the vote. The conservative Christian candidate Rick Santorum walked away wuith 13 per cent, while Ron Paul, whose attacks on aid to Israel have made him unpopular with Jewish groups, took only seven per cent.
The race now moves to Nevada, the home state of Mr Gingrich's biggest financial backer, Jewish casino mogul Sheldon Adelson.