Republican Senator Judd Gregg has withdrawn as President Barack Obama's nominee to be commerce secretary, another blow to the president's attempt to broaden support across party lines.
Mr Gregg said he was pulling out because of differences with the Democratic president over issues including the economic stimulus package and the country's census, which the Commerce Department would be responsible for implementing.
"We are functioning from a different set of views on many critical items of policy," he said.
Several Republicans in Congress have complained the Obama administration was taking control of the count away from the Commerce Department - a politically sensitive move as the 2010 census will help determine redistricting of congressional seats.
Mr Gregg said there was nothing in background checks that had played a role in his decision, a problem that has plagued other nominees.
President Obama's first selection for the job, New Mexico Governor Bill Richardson, withdrew because he was facing a legal inquiry.
In addition to these two withdrawals, Mr Obama has seen two high-profile nominations implode because of tax problems -- former Senator Tom Daschle to head the Department of Health and Human Services and Nancy Killefer to be the country's chief performance officer.
Treasury Secretary Timothy Geithner barely squeaked through his Senate confirmation process because he failed to pay certain taxes on time.