Barack Obama told a group of Florida donors Friday night that Republicans will try to make voters afraid of him, and suggested they would use his race to scare up votes for John McCain. Apparently girding for a nasty general election fight, the Illinois senator has in recent days predicted that independent GOP groups are waiting in the wings to attack him, and said his presumptive GOP rival is already “fear-mongering” when it comes to foreign policy. But his comments Friday night in Jacksonville, Fla., seemed to reflect elevated concerns that his campaign to be the first black president would...