The big news Monday night was that President Trump is apparently thinking about firing the special counsel in charge of the federal Russia investigation, Robert S. Mueller III.

The bigger news is that Trump actually needs to be talked out of this.

Newsmax chief executive and Trump confidant Christopher Ruddy took to PBS in an interview that aired Monday evening to say he thought Trump was "considering perhaps terminating" the recently appointed Mueller. Ruddy said this shortly after visiting the White House, it should be noted, which suggests that it didn't come out of nowhere. And it seemed to be as much a warning as a trial balloon; even before that interview aired, Ruddy and others were warning Trump strongly against that course of action.

"It could trigger something well beyond anything they ever imagined," Ruddy told Politico. "I think firing Mueller could trigger an impeachment process. It could be very dangerous. I don’t think it’d be very smart at all."

And here's former Trump campaign communications director Jason Miller:

The White House, for what it's worth, is trying to tamp down the story -- but it's not ruling out the possibility either. A late-night statement from press secretary Sean Spicer suggested Ruddy was speaking out of turn, which Ruddy pushed back against. Plenty of reports indicated Trump was being strongly advised against this.

But assuming Trump is actually considering this -- even a little bit -- this is the central problem with Trump's increasingly embattled presidency: He broke all the political rules and disregarded his advisers' exhortations, and he still won the presidency. As president, he assumes he can continue to do whatever appears to serve him personally and get away with it, even when advised not to by the people he's supposed to trust.

Former FBI director Robert S. Mueller III has been appointed special counsel to oversee an investigation of possible Russian interference in the 2016 presidential election. Here's what you should know about Mueller. (Amber Ferguson/The Washington Post)

It's difficult to say whether firing Mueller would lead to the impeachment that Ruddy fears; Trump, after all, fired James B. Comey as FBI director and has (thus far) lived to tell the tale. There have been so many things that people such as me and Ruddy told him he couldn't or shouldn't do, only to have Trump do them and then win the GOP nomination ... and then the presidency ... and then keep the Republican Party almost completely united behind his presidency. That's a recipe for hubris.

That said, firing the two people heading up the Russia investigation in the span of a little more than a month -- including one recently appointed by the Justice Department -- would seem to be very difficult to justify. Indeed, if you want to make it look as if you have something to hide, there are few better ways to do it. (And Comey is hardly Trump's only sin on that front.)

But whether firing Mueller is the straw that breaks the camel's back -- and far be it from me to predict that -- it's instructive that Trump is even considering it and folks such as Ruddy and Miller see the need to prosecute this publicly. And whether Trump goes against their advice this time, it seems only a matter of time before he finally does something that those around him almost universally agree is a very bad, camel-back-breaking idea -- and is a very bad, camel-back-breaking idea.

For however much Trump has survived his improprieties on the campaign trail and as president, he's still a phenomenally unpopular president. Both Quinnipiac University and Gallup over the past week have shown Trump's numbers hitting a new low. The GOP base is largely intact, but even that has shown signs of cracking amid the almost-constant pressure that Trump has played a big role in applying.

The fact that Ruddy and Miller even need to go on the airwaves and tell him to avoid such an obviously bad course of action suggests, whether it's this or something else, Trump will at some point be tempted to take things too far, in a way that might -- finally and permanently -- do him the kind of damage he hasn't done yet.

The Washington Post's Devlin Barrett explains the Justice Department's decision to appoint Robert Mueller as special counsel to investigate possible connections between the Trump campaign and Russian officials. (Peter Stevenson,Jason Aldag,Whitney Leaming/The Washington Post)