Chris Christie, an aggressive former prosecutor who racked up a perfect conviction rate in public corruption cases and became the darling of New Jersey's Republican Party establishment, has unseated the deep-pocketed but unpopular Gov. Jon Corzine.Christie, 47, on Tuesday became the first member of his party in a dozen years to win a statewide contest in heavily Democratic New Jersey. President Barack Obama invested heavily in the race, campaigning with Corzine five times on three separate visits.With 75 percent of precincts reporting, Christie had 50 percent of the vote compared to 44 percent for Corzine. Independent candidate Chris Daggett, who at one point had been feared as a potential spoiler, had about 5 percent.Christie accepted public financing in the race against the wealthy incumbent and was outspent by more than $12 million. He did get financial help from the Republican Governors Association and other national Republican groups, which bought television time in the pricey New York and Philadelphia media markets.