Chief of Staff Mick Mulvaney with Donald Trump (Saul Loeb/AFP/Getty)

Senate Republicans are in disarray over the Trump Administration’s Federal budget, struggling to reach an agreement with the White House — and, as Democrats are left out, raising the prospects of another government shutdown, deep spending cuts, and even a default.

GOP leaders have spent months trying to bring around Donald Trump to a bipartisan deal that funding the government and raising the limit on federal borrowing this fall, but have failed to make a breakthrough. A budget meeting at the Capitol this week between key Senate Republicans, including Majority Leader Mitch McConnell and senior White House officials, excluded Democrats.

“We’re negotiating with ourselves right now,” says Senate Appropriations Chairman Richard Shelby. “The President, the Administration has some views, maybe, that are a little different sometimes than the Senate Republicans have. So we’re trying to see if we can be together as best we can.”

The Trump Administration never presented a coherent budget in its first two years in office, with repeated emergency funding measure and a record-setting lapse. Support of the military and certain Government services was finally secured through 2020, but Trump shut down the Government for 35 days in December and January in a failed effort to get Congressional funding of his Wall with Mexico.

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To avert a new shutdown, agreement on funding must be reached by October 1. The federal debt limit must be raised, to avoid failure to pay obligations and a possible default. By the end of the year, an accord is needed to lift budget caps which would cut $125 billion from domestic and military programs.

Legislators and analysts says the relationship between White House Chief of Staff Mick Mulvaney, who advocated sharp spending cuts, and GOP legislators is frayed. Mulvaney is resisting a bipartisan deal to raise domestic and military spending caps, even after McConnell met privately with Trump last month and got Trump’s blessing to proceed.

An administration official said Trump has encouraged McConnell to get a good deal, but has not offered carte blanche for a budget agreement with a significant rise in domestic spending.

Administration officials and Senate GOP aides say Mulvaney and the White House favor continuance of existing spending levels or striking a one-year deal, rather than the two-year deal that legislators in both parties favor.

Sen. Shelby has been caustic about Mulvaney, implying that the Chief of Staff has not been constructive, and Democrat House Speaker Nancy Pelosi — who says there will be no vote on the debt limit until a spending deal is reached — said she is sceptical of negotiations “when Mick Mulvaney takes the lead”.

“Let’s hope the Republicans can get their act together,” Senate Minority Leader Charles Schumer said last week.