ABOARD USS HARRY S. TRUMAN (AP) -- Around Iraq's borders, the Pentagon is struggling to persuade allies to host U.S. troops and warplanes needed for a possible attack. At sea, however, America's military power is unhindered and growing to possibly the biggest concentration of warships since the 1991 Gulf War. Imposing naval flotillas - with aircraft carriers as their mighty centerpieces - are taking greater prominence in strategic planning for a possible war against Iraq as obstacles are raised to ground deployments, officers say. "I think all of the aircraft carriers will serve as a floating air base," said Capt....