WASHINGTON - Conservatives and voters troubled by abortion and illegal immigration were backing Mitt Romney as he fought for victory in Florida's Republican presidential primary on Tuesday. Lining up behind John McCain's bid were party moderates, Hispanics and the state's numerous older voters. As the two struggled for a triumph that could provide momentum for next week's Super Tuesday voting by nearly half the states, they were dividing Floridians along generational lines, according to preliminary results from exit polls of voters conducted for The Associated Press and the television networks. McCain was doing best among the oldest voters, while Romney's...