WASHINGTON (AP) — The Trump administration and Congress face a daunting set of budget-related deadlines in the coming weeks. Blowing them could upend global financial markets and cause a partial government shutdown.

What you need to know about next month's three-car pileup of must-do fiscal business, the prospects for resolution, and the consequences of failure:

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DEBT DILEMMA

The problem: The most important piece of business is the need to increase the United States' $19.9 trillion debt limit to permit the government to continue borrowing money to pay its bills, including Social Security and interest payments. The government hit its borrowing cap in March, but Treasury Secretary Steven Mnuchin has been using a well-worn set of accounting moves to free up cash. Nevertheless, Mnuchin says the debt ceiling needs to be raised by Sept. 29 to avert the risk of a first-ever U.S. default.

What's next? Since Republicans control both Congress and the White House, it's their responsibility to ensure that the government doesn't default. In the past, that would have meant that Republicans would have to put up virtually all of the votes. During Democratic President Barack Obama's recent tenure, congressional Republicans surrendered to Obama's demand for a debt measure that was "clean" — no GOP provisions — provided Democrats produce almost all of the votes. Trump is demanding a clean debt bill, too, but tea party lawmakers and outside conservative groups are demanding spending cuts as the price for increasing the debt limit.

"Our nation's structural deficit is driven by historically irresponsible levels of federal spending. Any increase in our nation's debt ceiling should be paired with serious spending reforms that begin reducing federal spending in real, meaningful ways," Dan Holler, vice president of the conservative policy advocate Heritage Action for America, said Monday in a statement.

Consequences of failure: It's never happened so nobody knows for sure, but financial experts warn that default on U.S. bond payments could roil financial markets. The government's credit rating would take a hit forcing it to pay higher interest rates. The government could likely "prioritize" payments to creditors — an option considered by some conservatives — but delays or failure to make other payments could have harsh, if unforeseen, consequences.

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SPENDING SHOWDOWN

The problem: The government's fiscal year ends Sept. 30 and legislation needs to be enacted to prevent a partial shutdown of federal agencies. At issue are the 12 annual spending bills funding agency operations. There's no agreement on what the overall spending level should be. Republican defense hawks want to lift a cap on Pentagon spending while Democrats are pressing for more money for domestic programs. Without a deal to increase spending, the annual appropriations bills are just sputtering along without a clear path to passage.

Trump's demand for a wall along the U.S.-Mexico border — resolutely opposed by Democrats and some Republicans — is a major sticking point. Trump has long promised Mexico would pay for the wall; instead, taxpayers would pick up the $1.6 billion first installment. (In a leaked transcript of a call with Mexican President Enrique Pena Nieto, Trump implored him to stop saying Mexico won't pay, while confessing "this is the least important thing that we are talking about.")

What's next? A stopgap spending measure known as a continuing resolution is sure to be needed to buy time to advance the unfinished spending bills. If a spending pact is reached, the bills could advance with help from Democrats, but if there's no broader bipartisan agreement it's possible that spending would simply be frozen at current levels by a yearlong continuing resolution. Nobody wants that.

Consequences of failure: A government shutdown, perhaps sparked by a battle over the wall, could come as early as October or perhaps later. But it wouldn't be the end of the world — at least for a while. While non-essential government programs would be shut down, the military, air traffic control, and federal law enforcement agencies would remain open. Benefits such as Social Security and Medicare would continue to be provided.

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BUDGET BATTLE

The problem: Republicans have yet to pass a budget plan for the upcoming 2018 fiscal year. Under Washington's arcane ways, passing a nonbinding budget plan is the only way to set in motion a special process for the GOP's top agenda item: rewriting the tax code. If Congress can pass a budget, Republicans controlling the Senate don't need to worry about a Democratic filibuster blocking any tax bill. A budget could also unlock a way for conservatives to win cuts to benefit programs over Democratic opposition.

What's next? Neither the Senate nor the House has passed a budget. House action has been held up by a battle between moderates and conservatives over whether to pair spending cuts with the filibuster-proof tax measure. Senate action has been on hold while the House struggles. September promises to be a critical month.

Consequences of failure. An impasse could doom the tax reform effort. Other than that, the consequences would be modest. Congress often fails to pass a budget resolution. Politically, it would be another blow to Republicans, who stumbled on health care.