After spending months testing the waters for a presidential run, Sen. Fred Thompson has made his candidacy official. "I am running for president of the United States," he said during a taping of NBC's "The Tonight Show with Jay Leno," drawing applause and cheers from the audience. Thompson will also talk about his decision to join the race for the Republican presidential nomination in a webcast scheduled to go online early Thursday. A five-day campaign tour will follow Thompson's announcement, sources said last week. Thompson will stump in Iowa, New Hampshire, South Carolina and Florida. Then it's on to Lawrenceburg,...