Senate Majority Leader Mitch McConnell, R-Ky., gave a foreboding warning from the Senate floor on Sunday.
But there are some noticeable differences between this shutdown and the last one, in 2013.
As in shutdowns past, federal services were carved into two categories - essential and non-essential - with the former set to carry on as normal.
Every federal agency has a specific contingency plan, in the case of a loss of funding, and you can look through them all here. Funds ran out at midnight Friday, leaving 48 hours before the most dramatic effect - the furloughing of almost a million federal employees - goes into effect.
"There's a little different philosophy on the shutdown from the Obama administration, which was, 'We're going to try to inflict pain on the American people, '" Daines said.
Matthew Rutter, an employee of State Cruises which operates ferries to islands said that the tourists weren't mad at government servicemen.
Sen. Steve Daines, R-Mont., said the Trump administration is trying to minimize the effects of the shutdown by keeping parks open, but he accused former President Barack Obama of doing the opposite.
Meanwhile, the City of Philadelphia said its services remain unaffected by the shutdown.
Lawmakers to grill state officials about missile alert mistake
Hawaii Emergency Management Agency spokesman Richard Repoza said the agency was trying to determine what happened. He also took emergency management officials to task for taking 30 minutes to issue a correction, prolonging panic.
Still, not everything remained open Saturday.
The Justice Department says criminal litigation will go on without interruption. Also, Robert Mueller's special counsel investigation, which is funded directly by Congress, not the Department of Justice, will still be in business.
Camila Guterrez, 18, was visiting with her family from Argentina on Sunday, their first time in NY. That won't be happening this year.
"There's absolutely a frustration [among park rangers]", Rott said on NPR's Weekend All Things Considered. "They could go out longer without being impacted; and some have none, so they'd be impacted immediately", Mulvaney said.
"How do you close down the Statue of Liberty?".
The Statue of Liberty and Ellis Island, closed since the government shut down Friday, will reopen for visitors Monday, with NY state picking up the tab for the federal workers who operate them, the state's Democratic governor, Andrew Cuomo, said Sunday.
In Arizona, Republican Governor Doug Ducey committed state funds to keep the Grand Canyon open, including trash removal, snow plowing and public restrooms, according to Ducey spokesman Patrick Ptak.