The senator is retiring, so he has released himself from President Ronald Reagan’s “11th Commandment."

Bob Corker once prided himself on being Donald Trump's closest adviser in the U.S. Senate.

Now he has become one of the president’s sharpest and most outspoken critics.

Ladies and gentlemen, we are just getting started on month 10 of the Trump presidency.

Corker, who just last year described Trump’s bluster as “inartful” when he campaigned with him, now describes the commander in chief as “untruthful.”

It’s really not surprising.

Any reasonable person, and especially someone of Corker’s status, could only take so much humiliation and insults in presidential tweets peppered throughout the month.

Too bad it couldn’t have happened sooner.

Now that Corker is not seeking re-election, he has released himself from President Ronald Reagan’s “11th Commandment,” making it taboo for a Republican to insult another Republican (a prohibition Trump never cared to follow).

► Read More:Bob Corker: Donald Trump is 'devolving' as president, intentionally dividing country

In media interviews Tuesday, Corker said he regretted supporting Trump for president and that the world’s most powerful man had debased and divided the United States of America, and was "devolving."

In a tweet that morning, he included the hashtag #AlertTheDayCareStaff when responding to more of Trump's cyberbullying.

Trump's Tuesday morning tweets inaccurately said Corker helped craft the Iran nuclear deal and that the senator is fighting a tax cut proposal.

He also said that Corker “couldn’t get elected dog catcher in Tennessee.” (Never mind that Corker has been elected senator twice and also mayor of Chattanooga.)

When Corker dared to respond, Trump shot back, calling the senator a “lightweight” and “incompetent,” and he mocked Corker’s height, calling him “liddle’ Bob Corker" — something he also tweeted on Oct. 10.

Stunning, but for those watching Trump, this behavior is nothing new. He frequently assails his rivals and critics.

► Read More:Editorial: Bob Corker stands tall for Tennessee

It took being repeatedly insulted publicly for Corker to snap, but as blues guitarist Otis Rush once said: “Nobody can tell you how the blues feel unless they have the blues.”

It is important to understand what Corker is saying about Trump, even through a thin veneer of politeness.

These three underlying messages should alarm all Americans, regardless of whether you voted for Trump, as Tennesseans did 2-to-1 over Hillary Clinton:

Trump lies. Trump divides. Trump is dangerous.

The correspondence I have received about Corker has generally fallen under one of two themes: “Corker is a hero” or “Corker is a traitor.”

► Read More:Donald Trump and Bob Corker continue public battle: A timeline of the escalating fight

I would say that Corker is taking off the blinders that so many good Americans wore to ignore the spectacle of Trump.

So, what now?

Trump is the lawfully elected president and, at this point, is expected to serve out at least one term in office. Maybe two.

Even without any significant legislative accomplishments and with a penchant for propaganda, Trump keeps on keeping on.

What Americans need to do is recognize and call out what he is: divisive, “untruthful” and unworthy of following his example.

We can become more politically engaged and work to uphold our democratic institutions while working to eradicate social and economic injustices from Appalachia to the inner cities.

We can contact our elected officials and vote in elections at all levels of government.

Republicans, Democrats and all others can do this together.

Corker is a canary in a coal mine, warning us to come to our senses.

He’s come to his senses. Let’s follow suit.

Before it’s too late.

David Plazas is the director of opinion and engagement for the USA TODAY NETWORK – Tennessee and opinion and engagement editor for The Tennessean. Call him at 615-259-8063, email him at dplazas@tennessean.com or tweet to him at @davidplazas.



