Arizonan Republican Sen. Jeff Flake has been known to be a critic of President Donald Trump since early in the 2016 election campaign, but his new book and an excerpt in POLITICO Magazine published Monday are sparking questions regarding his career’s future.

In his new book, The Conscience of a Conservative: A Rejection of Destructive Politics and a Return to Principle, Flake does not yield to countless pleas from GOP lawmakers for civility and union within the party and instead argues that Republicans are to blame for enabling Trump for too long.

According to Flake, his party can no longer approach this presidency as normal and doing so requires “a determined suspension of critical faculties. And tremendous powers of denial.”

Flake is a fiscal conservative who opposes expansion of gun control and internet privacy. He has served as the as Arizona senator alongside John McCain since 2013. He relies on the support from conservatives and he is up for reelection in 2018. This honest, and risky, condemnation of his own party members and the Executive Branch could potentially play into effect come 2018.

And, he’s already not very popular among his constituents.

Last month, Morning Consultant- POLITICO’s non-partisan polling partner- ranked Flake third-highest in disapproval ratings. Flake was only slightly more favorable than Sen. John McCain (R-Ariz.) who ranked second and Sen. Mitch McConnell (R-KY.) who topped the list.

Just as he argues that Republicans are responsible for Trump, Flake says only Republicans can make it right.

“And so, that unnerving silence in the face of an erratic executive branch is an abdication, and those in positions of leadership bear particular responsibility.”

The essay in POLITICO ends in a call for action.

Flake says Republicans should not hesitate to speak out against Trump when he does something to hinder the party’s ability to grow and speak to a larger audience. The Republicans, Flake says, should defend the “institutions” and “prerogatives” that work well, citing the Senate filibuster that Trump has been tweeting about getting rid of. Additionally, he warns his colleagues to be wary of "Populist and protectionist policies" and stand up to Trump’s views on free trade.

But the Arizonan senator is not the only Senate member criticizing Trump this week.

On the TODAY show Tuesday, Sen. Lindsey Graham (R-S.C.) spoke freely about his disapproval of the president’s misleading statement’s on Donald Trump Jr.’s Russian meetings in June of last year. He said Trump should “focus like a laser” on health care and “stop the chaos.”