Former GOP Rep. Jim Nussle, President Bush's nominee to run the White House budget office, must overcome several hurdles to win confirmation before the Senate's summer break.

The Iowa Republican helped his cause Thursday with an appearance before the Senate Budget Committee, said Kent Conrad, D-N.D., the committee chairman.

Conrad said he respects and likes Nussle, but he and other senators, including a top Republican, appear to be using the nomination to win concessions from the White House on other matters.

The White House hopes Nussle can be confirmed quickly so he can participate in negotiations on Capitol Hill this fall over the 12 annual appropriations bills and lead the preparation of Bush's next budget. The spending plan for the budget year that begins Oct. 1, 2008, is to be submitted to Congress in February.

But Democrats are clearly worried about a train wreck on the current appropriations bills. Bush has threatened to veto most of them for exceeding his requests. There is growing concern about the possibility of one big spending bill at year's end, the kind of measure subject to ridicule for "pork" projects and unrelated policy items.

Democrats are hoping to use leverage over Nussle's confirmation to force talks with the White House to reach an accommodation over the appropriations bills. Talks at the White House are expected next week. The Senate's vacation is scheduled to begin Aug. 6.

"This meeting at the White House has a bearing on all of this," Conrad said.

So, too, do the frustrations of Republican Pete Domenici of New Mexico, one of the Senate's most senior members.

Domenici says the administration is dragging its heels in putting in place a federal loan guarantee program for clean energy projects authorized by an energy law passed two years ago.

Domenici spelled out directly what Conrad would only hint at: Nussle's nomination is on hold until lawmakers squeeze some concessions.

"It's the most serious problem he's got," Domenici said of his demands. "They've got to fix it."

Nussle did well at the almost two-hour hearing, just as he did Tuesday at a hearing of the Senate Homeland Security and Governmental Affairs Committee. He defended Bush's budget policies while showing deference to the senators whose support he needs for confirmation.

"I look forward to helping develop policies that will keep us on track to balance the budget by 2012," Nussle said.

Nussle earned a reputation as a partisan combatant in his 16 years in the House. It is a label that was not entirely fair, said the chairman of the House Budget Committee, Rep. John Spratt Jr., D-S.C. He said Nussle had treated Democrats fairly in his six years as chairman of that committee.

Nussle, 47, left Congress last year after a failed bid for governor of Iowa. His relationship with the president dates to 1999, when Bush was running for the first time and Nussle endorsed him for the Iowa caucuses, an important early test in the nominating process.