Why did the U.S. government shut down and how long could it last?

With the U.S. government officially shut down , how long could the closure last and why is it happening?

Roughly 750,000 federal workers are expected to be furloughed, some potentially fired by the Trump administration. Many offices will be shuttered , perhaps permanently, as President Donald Trump vowed to “do things that are irreversible, that are bad” as retribution.

Here's what to know:

Why did the government shut down?

The Democrats picked this fight , which was unusual for the party that prefers to keep government running, but their voters are eager to challenge the president’s second-term agenda. Democrats are demanding funding for health care subsidies that are expiring for millions of people under the Affordable Care Act, causing the insurance premiums to spike