Clint Williamson is an American

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 lawyer and diplomat (see John Clint Williamson for full biography).
In 2006 he was appointed Ambassador-at-large for war crimes issues.
He is the State Department official responsible for negotiating another home for Guantanamo captives who can't be returned to their home countries.

On 16 October 2008 Williamson, the State Department

United States Department of State

The United States Department of State , is the United States federal executive department responsible for international relations of the United States, equivalent to the foreign ministries of other countries...

 official responsible for negotiating a new home for the captives, complained that the Justice Department's recent description of the Uyghurs had undermined his efforts.
The Justice Department had recently filed an emergency motion objecting to transferring the Uyghur captives in Guantanamo to the United States.