Kerry Positioner... The Boston Globe reports on the two new ads out of the Bush and Kerry campaigns: The image was simply too much for senior Bush media strategists to resist: Senator John F. Kerry windsurfing off Nantucket, his boat twisting back and forth in the gusty air, the very maneuver Republicans have accused the Democratic candidate of making on important policy issues for months. ''I thought it so perfectly conveyed the message," said senior adviser Mark McKinnon, who quickly grabbed the footage of Kerry, shot by news crews during the Republican National Convention, to turn it into...