Here is President Obama's statement, as released by the White House press office:
Over the past two and a half years, George Mitchell has worked as a tireless advocate for peace as the U.S. Special Envoy for the Middle East. His deep commitment to resolving conflict and advancing democracy has contributed immeasurably to the goal of two states living side by side in peace and security.
George told me when he took this job that he would put in a couple of years, and I’m so glad he did. He is – by any measure – one of the finest public servants that our nation has ever had. Even though he already had an extraordinary legacy – serving the people of Maine, leading the Senate, and bringing peace to Northern Ireland – he took on the toughest job imaginable and worked grueling hours to advance the interests of the United States and the cause of peace.
As he returns to his family, George leaves behind a proud legacy of dedicated public service and the country owes him a debt of gratitude for his extraordinary commitment.
As a nation, we remain committed to peace in the Middle East and to building on George’s hard work and progress toward achieving this goal. Secretary Clinton has asked the Deputy Middle East Envoy, David Hale to serve as the Acting Envoy and I have every confidence in David’s ability to continue to make progress in this important effort.