This is the longest shutdown in US history

Tribes that rely on federal funds for services, such as health clinics and food pantries, are affected by the shutdown.

About 1.9 million Native Americans and Alaska Natives get funding from the Bureau of Indian Affairs, which is operated by the Department of the Interior, one of the agencies hit by the shutdown.

For one tribe of Chippewa Indians in Michigan, the cost amounts to $100,000 each day the government is shut down, The New York Times reported.

President Trump is digging in his heels on his demand for a border wall, telling aides and allies that he believes he is winning the battle for public support.

Over the last 24 hours, Trump has privately touted a Washington Post-ABC News poll indicating that public support for a border wall has increased to 42% from 34% last year, a source familiar with his comments told CNN.

But a CNN/SSRS survey published Sunday shows a majority of the public blames the President, with 55% saying he is more responsible for the shutdown than are Democrats in Congress, while 32% say the blame rests mostly with the Democrats.

CNN's Omar Jimenez shot video of the line of people waiting to go through security at the Hartsfield-Jackson Atlanta International Airport.

The line wraps through baggage claim:

Earlier today, the airport's website estimated that wait times to get through security were more than an hour for some checkpoints.

Elise Durham, the airport’s director of communications, told CNN the long security lines were in part due to short staffing at Transportation Security Administration checkpoints.

While the lines are long, they are moving, Durham said. 

About 380,000 federal employees are required to stay home, while another 420,000 must work without pay. Many of them missed their first paychecks on Friday.

But congressional lawmakers and President Trump himself aren't missing any paychecks.

That's because the salaries of the President and members of Congress are written into the Constitution and aren't funded through annual appropriations.

That said, remember:

We're entering the fourth full week of the government shutdown, and talks are frozen.

House and Senate are both scheduled to come back into session this afternoon — but things are a little in flux due to the weather and subsequent closure of the federal government in Washington. 

So there's not much on today's agenda: There are currently no meetings scheduled and no new proposals being traded, aides in both parties say. 

Air traffic controllers are starting to feel the pressure from the partial government shutdown, according to Dan McCabe, a spokesman with the National Air Traffic Controllers Association. 

McCabe expressed concern about the impact the partial shutdown will have on the Super Bowl traffic that will flow through Atlanta's Hartsfield-Jackson International Airport in the coming weeks.

Remember: It's still safe to fly. While agencies like the Transportation Security Administration and the Federal Aviation Administration are understaffed because of the shutdown, experts say there's no reason to believe safety is compromised.

Security at airport checkpoints across the country is just as effective as ever, and average wait times are within TSA standards, an agency spokesman said. 

But things could get less safe over time: Just because air travel is still safe now does not mean that a prolonged government shutdown wouldn't have a potentially dangerous impact.

Issues like understaffing and employees quitting will only get worse with time.

The Hartsfield-Jackson Atlanta International Airport is struggling with TSA short staffing.

The airport’s Director of Communications, Elise Durham, told CNN the long security lines happening this morning at the airport are in part due to short staffing at TSA checkpoints.

While the lines are long, they are moving, Durham said. 

Earlier today, the airport's website estimated that wait times to get through security was more than an hour for some checkpoints.

Tim Babcock and Jay Anthony arrived at Atlanta Hartsfield-Jackson International Airport at 7 a.m. for a 10:15 a.m. flight to Dallas. The lines for security were so long that they're winding around inside the airport.

Here's the footage they shot:

Sen. Lindsey Graham said Sunday he advised the President to agree to re-open the government for three weeks, hold negotiations over border security and the wall, and if they ended up failing, then declare a national emergency. 

What this means: Don’t read this as a sign that Graham is fleeing the President’s side — this is far more about Graham understanding that negotiations are more fruitful with a new deadline (or anvil hanging over one’s head) than anything else. That's something that simply doesn’t exist in this current scenario, where there is no deadline — or end to a shutdown in sight.

But it is worth noting that Graham has repeatedly tried to find ways to re-open the government and set the stage for future negotiations over a period of time.

And remember: the President explicitly asked Speaker of the House Nancy Pelosi in the Situation Room if she would give him money for his border wall in a month if he agreed to immediately open the government. Pelosi said no.

As Washington DC is snowed in, shutdown talks are still at a complete and total impasse. It's day 24 of the shutdown, and things are just stuck in the same place as they have been for three weeks. Period. 

Bottom line: The dynamics haven’t changed. Between President Trump and Democratic leaders, someone will have to blink, and neither side is either willing — or, according to key players on both sides, currently has the political incentive — to do so. The expectation at the moment is that this week will be just as fruitless as the last. 

This weekend, CNN's Phil Mattingly polled seven senior GOP and Democratic aides who have been involved in these fights for years about how they thought this would end. While everyone had ideas and theories, not one could give a firm, confident answer on the way out.

The reason why was probably best encapsulated by this, from a GOP aide: