The Note: Two senators say 'enough' to Trump, but will others agree?

— -- The TAKE with Rick Klein

"Enough."

That was the plea from Sen. Jeff Flake on the Senate floor, capping an extraordinary day that saw not one but two Republican senators all but declare that the president of the United States is unfit for the presidency.

Viewed one way, the exits of Flake and Sen. Bob Corker mark a pair of resounding victories for Trumpist forces who are only too happy to see President Trump taken on by the GOP establishment.

But viewed another way – viewed the way Flake and Corker intended – this double-barreled critique of the president is a fundamental challenge to those who will continue to serve in government when Flake and Corker are gone. That's the story from here – how the words of Flake and Corker can or cannot linger in this Trump-driven news atmosphere.

Two pillars of the Republican Party, considered strong and loyal conservatives since before Trump even called himself a Republican, are publicly and loudly saying that the president's behavior and conduct is neither normal nor acceptable.

This can't be, or can't be only, about whether Trump supporters will abandon him; they will not.

This can be, and this has to be, about whether those who serve alongside Trump will at some point agree with Flake when he said, "enough."

The RUNDOWN with MaryAlice Parks

In not seeking re-election, Senators Jeff Flake and Bob Corker are not only free to speak their mind, but also free from political pressure to deliver.

While other Republican lawmakers are legitimately worried about conversations with voters over the holidays if they have nothing to show for a year in control of Washington -- so worried in fact they might quickly concede around the edges on budget or tax questions -- Flake and Corker have no reason to bend.

That has the potential to disrupt some big whip counts in big ways. This White House and Senate Majority Leader Mitch McConnell have no votes to spare.

On the other hand, Corker and Flake are both stalwart conservatives and did not mention policies or the president's "Make America Great Again" agenda in their blistering remarks yesterday.

Their focus was on, as they said, a flagrant disregard for the truth and other behaviors from this White House.

What's still more likely to derail legislative victories is the president's scant and often shifting guidance on which proposals he wants to sign.

The TIP with Aaron Katersky and John Santucci

The U.S. attorney for the Southern District of New York in Manhattan has opened an investigation into possible money laundering by former Trump campaign chairman Paul Manafort, a source with direct knowledge of the situation has confirmed to ABC News.

A spokesperson for Manafort declined to comment to ABC News on Tuesday night.

Manafort is already under investigation by special counsel Robert Mueller as part of the probe into possible collusion between the Trump campaign and the Russian government.

Additionally, Manafort has been under investigation for possible criminality in New York State by Attorney General Eric Schneiderman. Both the Attorney General and Southern District New York offices are cooperating with the Mueller investigation.

The source who confirmed that the U.S. attorney for the Southern District of New York has opened an investigation -- which was first reported by The Wall Street Journal -- points out that it is not uncommon for multiple investigations to be open by different levels of government.

WHAT YOU NEED TO KNOW TODAY:

QUOTE OF THE DAY

"I rise today to say: Enough. We must dedicate ourselves to making sure that the anomalous never becomes normal. With respect and humility, I must say that we have fooled ourselves for long enough that a pivot to governing is right around the corner, a return to civility and stability right behind it. We know better than that." --Sen. Jeff Flake during his speech announcing he will not seek re-election.

NEED TO READ

The Note is a daily ABC News feature that highlights the key political moments of the day ahead. Please check back tomorrow for the latest.