At the stroke of midnight, the federal government began shutting down because Congress was unable to agree on a spending bill for fiscal year 2014, which starts Tuesday. Although funding the government is one of the most essential duties of the Congress, the Republican-controlled House of Representatives and Democratic-controlled Senate find themselves bitterly at odds over funding for the Patient Protection and Affordable Care Act, or "Obamacare."
House Republicans passed a resolution that would fund the government to the tune of $986bn until December 15, but would delay the implementation of the Affordable Care Act, the president's signature domestic legislation.
"The American people don't want the government to shut down and they don't want Obamacare," declared Speaker John Boehner (R-Ohio) after the vote. "The House has listened to the American people. Now it's time for the United States Senate to listen to them as well."
For Senate Democrats, however, this is a non-starter. Senate Majority Leader Harry Reid (D-Nev.) stated bluntly, "Any bill that defunds Obamacare is dead."
Twice on Monday the Senate rejected House proposals by votes of 54-46.
A shutdown will mean that nearly 800,000 of some 3.3 million federal employees will be furloughed. CNN has compiled this comprehensive list of federal agencies and the extent to which a shutdown will affect them.
Going forward, it is unclear whether the House Republicans will settle for a compromise that does not defund or delay Obamacare. If not, the shutdown could last for a very long time, as Senate Democrats and the White House appear resolute. Last year the Supreme Court ruled the Affordable Care Act constitutional, and Obama won re-election against Mitt Romney, who ran in part on a pledge to repeal Obamacare.
The last time the federal government experienced a shutdown was in 1995 and 1996 after President Clinton vetoed a Republican-passed spending bill. The government shut down on two separate occasions between November and January and lasted a total of 28 days.
A CNN poll indicates that in the event of a shutdown, 46% would blame congressional Republicans, while 36% would point the finger at President Obama.