WASHINGTON – Conservative Democrats in the House rebelled against their party leaders Thursday, raising concerns about the cost of President Barack Obama's health care overhaul and seeking to put the brakes on legislation. The fiscally conservative Blue Dog Coalition planned to present a letter to House Democratic leaders asking for more time, members of the group told The Associated Press. Democratic Rep. Mike Ross of Arkansas said that if the Democrats' liberal legislative plan came to the floor as proposed, an "overwhelming majority" of his group would oppose it. The Blue Dogs claim 52 members, so that could endanger the...