Election Republican politician’s campaign get a boostU.S. presidential candidate Mitt Romney on Tuesday bagged double wins in primary battles in Arizona and Michigan, the state where he grew up.

According to projections by major U.S. TV networks, Romney, the former Massachusetts governor, won easily in Arizona, defeating main rival Rick Santorum, the former Pennsylvania senator, with double-digit edge. But the main fight of the day was centered around Michigan, a state which was supposed to be Romney’s backyard, where his father served as a popular governor. Poll results before the primary showed him in dead heat with Santorum, prompting pundits to speculate what a loss in his childhood home meant to the candidate and to the GOP race.With about 88 percent of votes counted, Romney led with 41 percent of the vote, followed by Santorum with 38 percent, U.S. broadcasters projected while the ballots were still being calculated. Texas congressman Ron Paul finished third with 12 percent of the vote.Former House Speaker Newt Gingrich, who mostly skipped the state, came in last at 7 percent.Santorum, who was campaigning in Michigan, told supporters that a month ago, "they didn’t know who we are, but they do now,” referring to his close second place finish. He called Romney to concede Michigan before going before the supporters. Romney, who spoke later, looked to his prospects in the campaign and vowed he would defeat PresidentBarack Obama should he becomes nominee, promising to bring about a better economy.Agencies