The White House announced today the worst kept secret in Washington — that diplomatic troubleshooter Dennis Ross was leaving the State Department to join the National Security Council staff, overseeing a range of hot spots — Iraq, Iran, Afghanistan, Pakistan and the Middle East.

Ross had been Hillary Rodham Clinton’s special adviser on the Persian Gulf and Southwest Asia (i.e., Iran.) He gained fame as the Middle East envoy in the Clinton administration and director of policy planning in the first Bush administration. The new job appears to come with significantly more responsibility.

In an e-mailed statement, spokesman Mike Hammer said National Security Adviser “General [James] Jones is pleased to announce an addition to our already strong National Security Staff. The addition is in the important Central Region that encompasses the Middle East, the Gulf, Afghanistan, Pakistan and South Asia. Gen. Jones is in the midst of a several day trip to this important region.

“Dennis Ross will become Special Assistant to the President and Senior Director for the Central Region with overall responsibility for the region. He will work with Don Camp, Senior Director for South Asia, Lt. Gen. Doug Lute, Special Assistant to the President and Senior Adviser and Coordinator for Afghanistan-Pakistan, Dan Shapiro, Senior Director for Near East and North Africa, and Puneet Talwar, Senior Director for the Gulf States, Iran and Iraq.”

One of Ross’s biggest boosters is said to be Thomas Donilon, the deputy national security adviser. According to Ross’s memoir, it was Donilon who played a key role in convincing him to stay on with Clinton after President George H.W. Bush was defeated.