Sen. Jeff Flake (R-Ariz.) is telling his fellow Republicans that they must address the mounting “chaos” within President Donald Trump’s White House or risk damaging the United States’ global positioning.

Flake, who just released a book in which he strongly criticizes the president, blasted Trump on Tuesday for rejecting the historically “measured” and “predictable” demeanor of the Republican Party.

“Chaos is the last thing that our allies and adversaries need to be seeing,” Flake said during an appearance on MSNBC’s “Morning Joe.” “And I’m afraid they’re seeing too much of that. ... I think we need to respect and utilize to hold our place in the world, and I wonder about our standing around the world now.”

Although Trump tweeted on Monday that there’s “no chaos” at the White House, his office has experienced a series of shake-ups in recent weeks ― and the world has looked on as the president has struggled to bring order to his office and country.

On July 21, Sean Spicer resigned as White House press secretary. Hours later, Anthony Scaramucci was named White House communications director.

Trump announced Friday that then-Secretary of Homeland Security John F. Kelly would take over the position of White House chief of staff from Reince Priebus. Priebus ― whom Scaramucci called a “paranoid schizophrenic” in a profanity-laced interview with The New Yorker last week ― had apparently quietly resigned from the position the day before. Scaramucci was booted from the Trump administration on Monday, reportedly at the behest of Kelly.

That unnerving silence in the face of an erratic executive branch is an abdication, and those in positions of leadership bear particular responsibility. Sen. Jeff Flake (R-Ariz.) in 'Conscience of a Conservative'

Flake on Tuesday released Conscience of a Conservative, a book condemning his party’s willingness to embrace “alternative facts, “anti-immigration fervor” and Trump himself. It shares its title with another work by a Republican senator from Arizona: a short but influential book that Barry Goldwater published in 1960.

Politico published an excerpt of Flake’s book on Monday. In a section titled “My Party Is In Denial About Donald Trump,” the senator accuses Republican lawmakers of “passively” observing the “unfolding drama” of the current presidency.

“That unnerving silence in the face of an erratic executive branch is an abdication, and those in positions of leadership bear particular responsibility,” wrote Flake, a Senate Foreign Relations Committee member.

“We have taken our ‘institutions conducive to freedom’ ... for granted as we have engaged in one of the more reckless periods of politics in our history,” he added.

Still, Flake’s words appear to speak louder than his actions. Despite expressing “concern” over Trump’s push for trade protectionism, Flake voted to confirm the president’s nominee for U.S. trade representative ― a man both Sen. John McCain (R-Ariz.) and Sen. Ben Sasse (R-Neb.) voted against because of his “alarming” skepticism over NAFTA.

Business Insider’s Josh Barro published a piece on Monday in which he slammed Flake for “falling down on the job.”

“There are Republicans in the Senate — Richard Burr and Chuck Grassley come to mind — who have been measured in their rhetoric but have taken substantial actions to hold Trump accountable for his lawlessness,” Barro wrote. “Flake is taking a less impressive approach: Complaining loudly about Trump and doing very little about him.”

CORRECTION: A pervious of this article incorrectly stated that Sen. Chuck Grassley (R-Iowa) voted against Trump’s nominee for U.S. trade representative. Grassley voted in favor of the nominee. Sen. Ben Sasse (R-Neb.) did not.