Sen. John McCain, R-Ariz., says his battle with brain cancer has given him more power to speak his mind – and the veteran does just that in an upcoming memoir in which he takes on President Donald Trump.

"[Trump] has declined to distinguish the actions of our government from the crimes of despotic ones," McCain writes in "The Restless Wave: Good Times, Just Causes, Great Fights, and Other Appreciations," an excerpt of which was released Monday by Apple News.

"The appearance of toughness, or a reality show facsimile of toughness, seems to matter more than any of our values."

In the book, which was written with Mark Salter and will be published by Simon & Schuster on May 22, McCain concedes this is his final term in the Senate, where he has served since 1987.

"If I hadn't admitted that to myself before this summer, a stage 4 cancer diagnosis acts as ungentle persuasion," McCain, 81, writes.

"I'm freer than colleagues who will face the voters again. I can speak my mind without fearing the consequences much. And I can vote my conscience without worry. I don't think I'm free to disregard my constituents' wishes, far from it.

"I don't feel excused from keeping pledges I made. Nor do I wish to harm my party's prospects. But I do feel a pressing responsibility to give Americans my best judgment."

McCain, a Vietnam War hero, is bothered by the "scarcity of humility" in the current political climate in America.

"I suspect it's never been in abundant supply in most human enterprises – and I don't mean modesty," he says. "Any politician worth a damn can fake modesty.

"Humility is the self-knowledge that you possess as much inherent dignity as anyone else, and not one bit more. Among its other virtues, humility makes for more productive politics."

The six-term senator recently underwent surgery for an intestinal infection at the Mayo Clinic in Phoenix.

In a promotional description for the book, McCain said: "I don't know how much longer I'll be here. Maybe I'll have another five years. Maybe, with the advances in oncology, they'll find new treatments for my cancer that will extend my life.

"Maybe I'll be gone before you read this. My predicament is, well, rather unpredictable. But I'm prepared for either contingency, or at least I'm getting prepared. I have some things I'd like to take care of first, some work that needs finishing, and some people I need to see. And I want to talk to my fellow Americans a little more if I may."



Simon & Schuster calls the book an "inspiring, moving, frank, and deeply personal memoir."