Hill has become the latest in a string of troubled nominations by the president, although Hill's fate is far from sealed.
Whereas others have succumbed to tax scandals, Hill's appointment ran into Republican complaints that he lacks experience in the Middle East and was too eager to strike a deal in inconclusive disarmament talks with North Korea.
As of late Friday, four Republican senators - Sam Brownback of Kansas, John McCain of Arizona, Lindsey Graham of South Carolina and John Ensign of Nevada
- said Obama should reconsider.
"I'm going to raise every objection that I can," Brownback said in an interview. "This would be very harmful to our efforts" to boost diplomacy in the Middle East.
In a bid to salvage his appointment, Hill asked to meet privately next week with at least two of the senators
- McCain and Brownback.
"The president believes he's got the right man for the job," White House press secretary Robert Gibbs said Friday.
Senate Majority Leader Harry Reid, D-Nev., and Sen. John Kerry, D-Mass., chairman of the Foreign Relations Committee, quickly defended Hill as well.
"Chris Hill is a strong, skilled and effective negotiator and an accomplished career foreign service officer who demonstrated his significant expertise in some of the most protracted and complex diplomatic challenges in the world, including those in North Korea and Bosnia," Reid said.
But Hill's confirmation was in doubt in a political climate marked by the Senate's thin margins. To be successful, Reid would have to round up a group of moderate Republicans to reach the 60 votes needed to cut off debate and end a potential filibuster by Brownback.
There are currently 56 Democratic senators and two independents who caucus with the Democrats. But one of those independents is Sen. Joe Lieberman of Connecticut, who had endorsed McCain for president and remains a close ally of the Arizona senator.
If Obama's push for Hill's appointment fails, there are limited options. The administration has already tapped a former top military officer
- Lt. Gen. Karl W. Eikenberry - for the other war-zone ambassadorship in Afghanistan. And there is a strong preference in the State Department and among many administration advisers to name a career diplomat with top-shelf credentials for the Iraq post.
There aren't many to choose from, at least among those still on the State Department payroll. The list gets smaller if limited to those with strong Middle East backgrounds.
Hill is probably the best-known of his crop of veteran diplomats - those who have held multiple ambassadorships as well as top jobs in Washington. As chief U.S. negotiator in the six-nation disarmament talks with North Korea, he became a media darling in Asia but a lightening rod for criticism from Republican conservatives who thought he was too willing to make concessions to try to prod Pyongyang to give up its nuclear weapons.