WASHINGTON (AP) — The Senate's top Democrat says Republicans are mounting a full-scale filibuster of Chuck Hagel's nomination to be President Barack Obama's secretary of defense. Majority Leader Harry Reid says Thursday there has never been a filibuster of a secretary of defense in the country's history. The Nevada senator says it's "shocking" and "tragic" that Republicans would block Hagel's nomination. Reid filed a motion Wednesday to limit debate and force a vote on Hagel's nomination, which is expected to be held Friday. While Democrats hold a 55-45 edge in the Senate and have the numbers to confirm Hagel on a majority vote, they need the backing of five Republicans to clear the way for an up-or-down vote on him.