WASHINGTON — Senate Republicans Thursday successfully blocked the nomination of Rep. Mel Watt to head up the federal agencies overseeing the real estate industry, only the second time a sitting member of Congress has had a nomination blocked since before the Civil War.

Only Sens. Richard Burr and Rob Portman broke ranks and voted for the North Carolina Democrat's nomination to head up the Federal Housing Finance Agency, which oversees Fannie Mae and Freddie Mac.

Republicans have raised repeated concerns about Watts' experience during the nomination process, arguing that Watt is too political and unqualified to oversee the enormously powerful federal loan companies.

Although a handful of current and former members have seen their nominations either withdrawn because of controversy, filibustering a nomination of a sitting lawmaker is unheard of in the modern era.

In fact, Watt joins only Rep. Caleb Cushing, who was nominated to head the Treasury Department by President John Tyler in 1843, as the second sitting member to be filibustered in more than 150 years, according to an analysis of voting records by the NAACP.

Civil rights activists decried the filibuster. "The Senate has not filibustered a sitting member of Congress since before the Civil War. And by denying a fair vote to a nominee with 40 years of experience in the housing sector is hyperpartisanship at its worse," said Nancy Zirkin, executive vice president of The Leadership Conference on Civil and Human Rights.