Sen. John McCain (R-AZ) makes a stunning confession in his soon-to-be-released memoir, which has been written as he battles a deadly brain cancer diagnosis.

“[The Iraq War] can’t be judged as anything other than a mistake, a very serious one, and I have to accept my share of the blame for it,” McCain writes in his book “The Restless Wave.”

This inconceivable admission comes from one of the war’s most ardent supporters, and one of the most hawkish Republican Senators of the 21st century.

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“McCain was strongly supportive of the Bush administration’s decision to invade Iraq and depose Saddam Hussein,” says a Cato article. “When it became evident that U.S. expectations of a rapid success in creating a stable, democratic Iraq were unrealistic, though, he did not join a majority of Americans in turning against the war. Already in November 2003, he was calling for the deployment of at least another division, ‘giving us the necessary manpower to conduct a focused counterinsurgency campaign across the Sunni triangle.'”

In 2005, when 66% of the country viewed the war as unfavorable, McCain kept pushing.

But Iraq was not the only place where McCain pushed for preemptive military intervention. He long-vied for a U.S. strike on Iran in order to halt their nuclear weapons development program.

“There is only one thing worse than military action, and that is a nuclear armed Iran,” he said. “Standing by while an odious regime with a history of support to terrorism develops weapons whose use by terrorists could literally kill millions of Americans is not a choice. It is an abdication.”

He once wanted to take out North Korea, too.

In 2002, McCain chided President George W. Bush and Secretary of State Colin Powell because they “publicly ruled out the use of force, although force could eventually prove to be the only means to prevent North Korea from acquiring a nuclear arsenal.”

As recently as December, McCain took a shot at President Donald J. Trump, with whom he has a long-standing feud, for not invading Syria and deposing Bashar Al-Assad:

Reports that Trump admin is willing to accept 4 more years of Assad’s rule in #Syria are deeply disturbing & would validate the de facto policy of 2 successive US admins that have failed to end the slaughter. https://t.co/mRwlnjS5MA

— John McCain (@SenJohnMcCain) December 13, 2017

“Reports that Trump admin is willing to accept 4 more years of Assad’s rule in Syria are deeply disturbing & would validate the de facto policy of 2 successive US admins that have failed to end the slaughter,” McCain wrote.

Why the warhawk has suddenly changed his tune on the Iraq war will remain a mystery until his book is released, and perhaps thereafter. For once, though, McCain is right about something: The Iraq War was a mistake.