Congress has averted for now a threatened government shutdown that would have disrupted many services, squeezed federal employees and roiled politics.

The threat was set aside late Saturday after Congress voted to keep agencies open until Nov. 17. Speaker Kevin McCarthy, R-Calif., dropped demands for steep spending cuts and relied on Democratic votes for House passage, before the Senate easily approved the measure Saturday night.

House Republicans, fueled by hard-right demands for lower spending, had been forcing a confrontation over federal spending.

In a shutdown, some government entities would be exempt — Social Security checks, for example, would still go out — and other functions would be severely curtailed. Federal agencies would cease all actions deemed nonessential, and many of the federal government’s roughly 2 million employees, as well as 2 million active-duty military troops and reservists, would not receive paychecks.

A look at what could happen in the event of a shutdown.

WHAT IS A GOVERNMENT SHUTDOWN?

A shutdown happens when Congress fails to pass some type of funding legislation that is signed into law by the president. Lawmakers are supposed to pass 12 different spending bills to fund agencies across the government, but the process is time-consuming. They often resort to passing a temporary extension, called a continuing resolution or CR, to allow the government to keep operating.

When no funding legislation is enacted, federal agencies must stop all nonessential work and would not send paychecks as long as the shutdown would last.

Although employees deemed essential to public safety such as air traffic controllers and law enforcement officers still have to report to work, other federal employees are furloughed. Under a 2019 law, those workers are slated to receive backpay once the funding impasse is resolved.

WHEN WOULD A SHUTDOWN BEGIN AND HOW LONG COULD IT LAST?

Government funding expires Oct. 1, the start of the federal budget year. A shutdown would have begun at 12:01 a.m. Sunday if Congress didn't pass a funding plan that the president could sign into law. The House and Senate averted this by approving a temporary funding bill keeping federal agencies open until Nov. 17, setting up another potential crisis if they fail to more fully fund government by then.

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There were fears that a potential stoppage could last weeks.

WHO DOES A SHUTDOWN AFFECT?

Millions of federal workers would face delayed paychecks, including many of the roughly 2 million military personnel and more than 2 million civilian workers across the nation.

Nearly 60% of federal workers are stationed in the Department of Defense, Veterans Affairs and Homeland Security.

While the military's active-duty troops and reservists would continue to work, more than half of the Department of Defense's civilian workforce — roughly 440,000 people — would be furloughed.

Across federal agencies, workers are stationed in all 50 states and have direct interaction with taxpayers — from Transportation Security Administration agents who operate security at airports to Postal Service workers who deliver mail.

Transportation Secretary Pete Buttigieg has said new training for air traffic controllers would have to be halted and an additional 1,000 controllers in the midst of training would have to be furloughed.

People applying for government services like clinical medical trials, firearm permits and passports could see delays if there was a shutdown.

Head Start programs serving more than 10,000 disadvantaged children would immediately lose federal funding. National parks would close.

Some federal offices would have to close or face shortened hours during a shutdown.

Businesses closely connected to the federal government, such as federal contractors or tourist services around national parks, could see disruptions and downturns.

Lawmakers warned that a shutdown could rattle financial markets. Goldman Sachs estimated that a shutdown would reduce economic growth by 0.2% every week it lasted, but growth would then bounce back after the government reopens.

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Others say any disruption in government services would have far-reaching impacts because it would shake confidence in the government to fulfill its basic duties.

WHAT ABOUT COURT CASES, THE WORK OF CONGRESS AND PRESIDENTIAL PAY?

The president and members of Congress would continue to work and get paid. Any members of their staff who were not deemed essential would be furloughed.

The Supreme Court would be unaffected by a short shutdown because it can draw on a pot of money provided by court fees, including charges for filing lawsuits and other documents, court spokeswoman Patricia McCabe said.

Even in a longer shutdown, the entire judiciary would not shut down, and decisions about what activities would continue would be made by each court around the country. The justices and all federal judges would continue to be paid because of the constitutional prohibition on reducing judges’ pay during their tenure, according to the Congressional Research Service.

Funding for the three special counsels appointed by Attorney General Merrick Garland would not be affected by a government shutdown because they are paid for through a permanent, indefinite appropriation, an area that has been exempted from shutdowns in the past.

That would mean that the two federal cases against Donald Trump, the former president, as well as the case against Hunter Biden, the son of President Joe Biden, would not be interrupted. Trump has demanded that Republicans defund the prosecutions against him as a condition of funding the government, declaring it their “last chance” to act.

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HAS THIS HAPPENED BEFORE?

Before the 1980s, lapses in government funding did not result in government operations significantly shuttering. But then-Attorney General Benjamin Civiletti, in a series of legal opinions in 1980 and 1981, argued that government agencies cannot legally operate during a funding gap.

Federal officials have since operated under an understanding they can make exemptions for functions that are “essential” for public safety and constitutional duties.

Since 1976, there have been 22 funding gaps, with 10 of them leading to workers being furloughed. But most of the significant shutdowns have taken place since Bill Clinton's presidency, when then-Speaker Newt Gingrich. R-Ga., and his conservative House majority demanded budget cuts.

The longest government shutdown happened between 2018 and 2019 when then-President Trump and congressional Democrats entered a standoff over his demand for funding for a border wall. The disruption lasted 35 days, through the holiday season, but was also only a partial government shutdown because Congress had passed some appropriations bills to fund parts of the government.

WHAT DOES IT TAKE TO END A SHUTDOWN?

It's the responsibility of Congress to fund the government. The House and Senate have to agree to fund the government, and the president has to sign the legislation into law.

Congress often has relied on a continuing resolution to provide stopgap money to open government offices at current levels as budget talks are underway. Money for pressing national priorities, such as emergency assistance for victims of natural disasters, is often attached to a short-term bill.