Mr. Short, one of the few administration officials with good relationships on both sides of the political aisle in Congress, said his primary mission between now and the end of the year was avoiding a reprise of the debt ceiling fight and passing some kind of tax overhaul.

He reiterated a Treasury Department demand that lawmakers take action on the debt limit before their August recess. But even the Trump administration is conflicted, internally, on the best approach.

Last week, the White House budget director, Mick Mulvaney, said he would like to see spending cuts or other policy changes the administration has been seeking to go along with a bill to raise the debt limit. This put him at odds with Steven Mnuchin, the Treasury secretary, who has urged a “clean” increase of the debt ceiling with no strings attached. Mr. Mulvaney said the administration as a whole had not settled on which was the best approach, but he insisted that the United States would not default on its debt.

Mr. Trump’s budget includes deep cuts to domestic programs and foreign aid, and at best has been received tepidly by Congress. Mr. Short also conceded that the health care bill that passed the House last month, which Mr. Trump has backed, was unlikely to pass the Senate intact.

But he dismissed the idea that the Republicans who control the legislative and executive branches had been handcuffed by internal ideological disputes and Mr. Trump’s troubles. He didn’t rule out passing an infrastructure bill this year, but did not make mention of it until pressed — even though it is the focus of Mr. Trump’s public schedule this week.