(CNN) California Sen. Dianne Feinstein is uniquely situated at the center of the ongoing probe into Russia's involvement in the 2016 election as she sits on both the Senate intelligence and judiciary committees. (She is the highest-ranking Democrat on the judiciary committee.) Feinstein's centrality to all of this means that when she talks, we would do well to listen.

And, man, did she have something to say Friday. Here's her full statement on President Donald Trump's latest tweets about the special counsel investigation being led by former FBI Director Bob Mueller:

"I'm growing increasingly concerned that the President will attempt to fire not only Robert Mueller, the special counsel investigating possible obstruction of justice, but also Deputy Attorney General Rosenstein who appointed Mueller.

"The message the President is sending through his tweets is that he believes the rule of law doesn't apply to him and that anyone who thinks otherwise will be fired. That's undemocratic on its face and a blatant violation of the President's oath of office.

"First of all, the President has no authority to fire Robert Mueller. That authority clearly lies with the attorney general—or in this case, because the attorney general has recused himself, with the deputy attorney general. Rosenstein testified under oath this week that he would not fire Mueller without good cause and that none exists.

"And second, if the President thinks he can fire Deputy Attorney General Rosenstein and replace him with someone who will shut down the investigation, he's in for a rude awakening. Even his staunchest supporters will balk at such a blatant effort to subvert the law.

"It's becoming clear to me that the President has embarked on an effort to undermine anyone with the ability to bring any misdeeds to light, be that Congress, the media or the Justice Department. The Senate should not let that happen. We're a nation of laws that apply equally to everyone, a lesson the President would be wise to learn."

Just a few lines worth reading again:

* "The message the President is sending through his tweets is that he believes the rule of law doesn't apply to him."

* "If the President thinks he can fire Deputy Attorney General Rosenstein and replace him with someone who will shut down the investigation, he's in for a rude awakening."

* "It's becoming clear to me that the President has embarked on an effort to undermine anyone with the ability to bring any misdeeds to light."

* "We're a nation of laws that apply equally to everyone, a lesson the President would be wise to learn."

Any one of those lines is a 99-mile-an-hour fastball thrown way, way inside. Taken all altogether, it's a statement very clearly designed to send a message to Trump.

That message? Enough! Time to start acting like a president.

To be clear: Feinstein is a Democrat. She represents one of the most Democratic states in the country and risks absolutely nothing, politically speaking, by issuing a statement like this one that blisters Trump.

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But she is also one of the institutions in the Senate, having spent the last 25 years in the chamber. Unlike her longtime colleague Barbara Boxer, who retired in 2016, Feinstein is not seen as terribly partisan and generally enjoys strong across-the-aisle relationships.

"Every conversation that I've had with her now that she's ranking member has been not only friendly, but has been productive, and these little heads-to-heads that you see us having when the committee's actually functioning, work things out right then."

In short: Feinstein isn't just a predictable partisan or someone who pops off at the slightest political provocation. This statement is a purposeful attempt to make clear that Trump has crossed a line and that he needs to take one big step back.

My prediction: He won't.