President Bush is turning to former Missouri Sen. John Danforth (search) to make the administration's Iraq case in the United Nations, choosing a Republican who was a Senate ally of his father and has been a troubleshooter for both Democratic and Republican presidents.

If confirmed by the Senate, as seems virtually certain, Danforth will succeed the current U.N. ambassador, John Negroponte (search), who will be moving to Iraq as Bush's ambassador to the new government there this summer.

Since 2001, Danforth has been Bush's special envoy to war-torn Sudan (search), where he has tried to mediate a peace agreement. He served in the Senate for 18 years and was on Bush's short list as a possible vice presidential choice in 2000.

The president made the announcement that he would nominate Danforth in a statement released while he was in Rome on a three-day European trip. The U.N.'s role in post-occupation Iraq will be a major topic in Bush's discussions with European leaders this weekend.

A lawyer with a practice in St. Louis, Danforth, 67, is a former attorney general of Missouri. An heir to the Ralston Purina fortune, he is also a licensed Episcopal priest and a graduate of Princeton University and Yale University's law school.

Bush nominated Negroponte in April to be the ambassador to Iraq's interim government, which is to gain sovereignty on June 30.

Danforth has been tapped before to tackle complex issues since his 1995 retirement from the Senate.

During the Clinton administration, he acted as special counsel appointed by then-Attorney General Janet Reno. He conducted a 14-month inquiry into the deaths in 1993 of about 80 Branch Davidians (search) in Waco, Texas. His investigation cleared the FBI of wrongdoing.

While in the Senate, he helped lead the confirmation battle for Supreme Court nominee Clarence Thomas, a former Danforth assistant who was nominated to the high court by the first President Bush. The senator's support was considered crucial in winning confirmation after sexual harassment accusations against Thomas by former aide Anita Hill.

Danforth is a political moderate who is popular among conservatives — for his anti-abortion stance among other reasons.

He was once quoted as saying he joined the Republican Party for "the same reason you sometimes choose which movie to see — the one with the shortest line."

He is married with five adult children.