The Note: Robert Mueller presents new political peril for President Donald Trump Trump's presidency faces a growing threat from probes that could expand.

The TAKE with Rick Klein

There was, for a very long time, quiet Robert Mueller. Then came a Mueller team that trafficked in legal obscurities and in directions that seemed like distractions. Now comes a special counsel's operation with a mission that is growing clear and direct.

As Mueller and prosecutors in New York hone in on questions of how Donald Trump became president, and potential crimes committed in that quest, his presidency faces a growing threat from probes potentially expanding in scope.

This more-politically minded Mueller makes the president's argument that anything "totally clears" him ring hollow. Trump's enemies are more freely talking about impeachment and his allies' support shows signs of fraying.

The paths out of this morass carry growing political risks for the president, as he seeks to install new leaders at the Department of Justice and inside his own White House.

Sen. Marco Rubio, R-Fla., made clear that he views the use of a pardon by Trump of former campaign chairman Paul Manafort or others charged by Mueller, an inappropriate remedy -- a "terrible mistake."

"Not only does it not pass the smell test," Rubio said on ABC's “This Week" Sunday, "I just think it undermines the reason why we have presidential pardons in the first place."

The RUNDOWN with MaryAlice Parks

Ironically, this week -- yes, the same week the president and his former associates find themselves in perhaps more political and legal peril than ever before, and where select Democrats are again chatting about avenues of impeachment -- we could see a number of headlines about bipartisanship in Washington.

First, the Senate is slated to vote on a resolution brought by two senators who often represent the far poles of the two parties: Sens. Mike Lee, R-Utah, and Bernie Sanders, I-Vt. The resolution is aimed at ending the U.S. military's current support of Saudi Arabia's involvement in the war in Yemen.

Then on Tuesday, Democratic House and Senate leaders Rep. Nancy Pelosi and Sen. Chuck Schumer also are scheduled to meet with Trump as talks of government funding continue before the new year. Both sides have expressed interest in reaching agreements on immigration and border security.

What's more, the White House, Sen. Rand Paul, R-Ky., and others likely will continue to work with Democrats to urge action from Republican Senate Majority Leader Mitch McConnell on criminal justice reform during this session of Congress.

The TIP with John Verhovek

Sens. Cory Booker and Kamala Harris each have said they'll decide on a presidential bid over the holidays. Former Vice President Joe Biden is openly discussing his qualifications to be the next commander in chief.

Presidential politics for 2020 are well under way, whether we've been able to fully digest the results of the midterms or not -- but the timing of the political jockeying will play out differently this cycle than any other in recent memory.

Early entrances will undoubtedly spur some of the heavy hitters like Biden or Sanders to make a decision earlier than they want, but some states are expected to expand early voting during the 2020 primaries, and the effect on the political calculus for campaigns could be significant.

Yes, who gets in the race -- and when -- matters. Perhaps, however, what matters more is when voters are able to make their voices heard and the overarching political mood of the country at the time.

THE PLAYLIST

ABC News' Start Here Podcast Monday morning's episode features ABC News' Mike Levine, who catches us up on the Friday court filings concerning former Trump associates Michael Cohen and Paul Manafort. And ABC News' Katherine Faulders explains why chief of staff John Kelly is leaving at the end of the year. http://apple.co/2HPocUL

WHAT YOU NEED TO KNOW TODAY

Former New York City Mayor Michael Bloomberg will appear on ABC's "The View" at 11 a.m. EST.

Trump is scheduled to eat lunch with Vice President Mike Pence at 12:30 p.m.

National Oceanic and Atmospheric Administration 'Explaining Extreme Events of 2017" report and discussion in Washington at 3 p.m.