The Note: Nervous laughter in Washington, when it should be quiet for the holidays

The TAKE with Rick Klein

The year is ending with neither a bang or a whimper but with whispered laughter -- the nervous kind -- over the fact that Washington officials are stuck in town and that one fewer general is going to be working for the Trump administration.

The tragicomedy that has settled over pre-holidays Washington is a fight over border security that could partially shutter, among other agencies, the Department of Homeland Security.

It happens at the same time that Defense Secretary James Mattis heads for the exit, a step behind a crop of Republican lawmakers who don’t want to see the end of this chapter, after voters rendered judgment last month.

President Donald Trump is set to blame Democrats for a potential shutdown, though he said last week he’d gladly own it -- over a wall that’s not really a wall -- to pay for something that Mexico was supposed to and that Congress most definitely doesn’t want to.

Mattis, meanwhile, was the last of the Trump generals, a curious group viewed simultaneously as protectors and enablers by erstwhile White House allies.

It’s an unsettling end to a week and a year that exposed rifts in the Republican Party, as well as serious vulnerabilities to the Trump presidency. Trump’s allies continue to do his legislative bidding -- but increasingly wonder if that’s worth the risk.

The RUNDOWN with Adam Kelsey

If a course correction from 2016 was the goal, Tom Perez said all the right things on Thursday when he announced that the Democratic National Committee plans to hold 12 presidential primary debates over the next two years, and potentially split the field into multiple sessions, assigning positions randomly.

The Bernie Sanders-sparked accusations of favoritism should subside this cycle, especially if we see some of the heavy-hitters like Joe Biden standing stage-right or being relegated to day two of a debate, but the question of the specific threshold to qualify for the events remains outstanding.

The DNC chairman played somewhat coy Thursday, referring to polling and grassroots fundraising as two components of the calculation.

There's no perfect solution. It's impossible for the party to include every interested politician and maintain a substantive debate without the format or length becoming unwieldy, but the candidates will likely be clamoring for continued transparency and clarity on the qualifications.

With tangible goals in mind, campaigns will know what they have to accomplish ahead of the first debate in June. But if the party puts off the decision until later, it'll appear again as if it's gaming the system to intentionally exclude some participants.

The TIP with Benjamin Siegel

Top Republicans and Democrats reacted to news of the Defense secretary's resignation with alarm Thursday night, expressing concerns about the chaos in the administration and the message his departure sends to the world.

But Senate Majority Leader Mitch McConnell's carefully worded reaction to the reasons why Mattis is leaving spoke volumes.

“I believe it’s essential that the United States maintain and strengthen the post-World War II alliances that have been carefully built by leaders in both parties. We must also maintain a clear-eyed understanding of our friends and foes, and recognize that nations like Russia are among the latter," McConnell said in a statement. “So I was sorry to learn that Secretary Mattis, who shares those clear principles, will soon depart the administration. But I am particularly distressed that he is resigning due to sharp differences with the president on these and other key aspects of America’s global leadership.

“It is regrettable that the president must now choose a new Secretary of Defense. But I urge him to select a leader who shares Secretary Mattis’s understanding of these vital principles and his total commitment to America’s servicemembers.”

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The Note is a daily ABC News feature that highlights the key political moments of the day ahead. The Note will be back on Wednesday, Jan. 2, 2019.