Be careful what you wish for. Democrats looking for ways to attack Donald Trump have been licking their chops at the prospect of a James Mattis tell-all memoir. Unfortunately for them, Mattis has indeed written such a book, but it tells all about Mattis’ observations of their front runner, Joe Biden, and his former boss Barack Obama.

The Washington Examiner got a sneak peek of Mattis’ new memoir Call Sign Chaos, and it’s not pretty. While Mattis warned of the risks of a sudden withdrawal in 2011, Biden refused to listen:

“I found him an admirable and amiable man. But he was past the point where he was willing to entertain a ‘good idea.’ He didn’t want to hear more; he wanted our forces out of Iraq. Whatever path led there fastest, he favored,” Mattis writes. “He exuded the confidence of a man whose mind was made up, perhaps even indifferent to considering the consequences were he judging the situation incorrectly.”

Biden reassured Mattis that Maliki wouldn’t eject all American troops from the country.

“Maliki wants us to stick around, because he does not see a future in Iraq otherwise,” Biden said. “I’ll bet you my vice presidency.”

Mattis doesn’t say whether he tried to collect on that bet. As he writes, “In October 2011, Prime Minister Maliki and President Obama agreed that all U.S. forces would leave at the end of the year.”

Mattis’ warnings proved prescient, as Maliki, free of American influence, went after Sunni politicians and districts, alienating a third of the country. “Iraq slipped back into escalating violence. It was like watching a car wreck in slow motion,” Mattis writes. A Sunni revolt and a weak Iraqi Army allowed al Qaeda-aligned terrorists to return in 2014, calling themselves the Islamic State.

Mattis told reporters last week that he won’t criticize a sitting president whose administration he served. It’s widely suspected that Mattis has no love for Donald Trump, and some of his remarks about leadership seem implicitly aimed at his former boss. When it comes to Trump’s retired predecessor, however, Mattis shows no such restraint. His assessment of Barack Obama doesn’t even carry the leavening of personal admiration that Mattis expresses about Biden:

Mattis summarizes his time commanding CENTCOM, overseeing military operations in the Middle East and Central Asia until Obama fired him, in harsh terms: “It was to be a time when I would witness duty and deceit, courage and cowardice, and, ultimately, strategic frustration.” The general was in charge of two wars, in Iraq and Afghanistan, though one ended on his watch — or so the president said. …

The White House “dealt with Iraq as a ‘one-off,’ as if the pullout of our troops there would have no regional implications, reinforcing our allies’ fears that we were abandoning them. I argued strongly that any vacuum left in our wake would be filled by Sunni terrorists and Iran.”

Mattis believes he was vindicated by events. Obama declared the war over, but “Iraq slipped back into escalating violence. It was like watching a car wreck in slow motion,” Mattis says. “All of this was predicted — and preventable.”

Obama made “catastrophic decisions” in Iraq, Mattis concludes. And he did so because he ignored the advice coming from multiple military and civilian advisers, thinking he knew better than all of them.

“At the top, then as now, there was an aura of omniscience. The assessments of the intelligence community, our diplomats, and our military had been excluded from the decision-making circle,” Mattis writes.

His continuing conflict with Obama over regional strategic issues led to his abrupt dismissal the next year, Mattis writes. After noting that he was known for “blunt speaking,” Mattis implicitly accuses Obama of cowardice in the manner in which he got cashiered:

He was relieved of command without even an official phone call.

“In December 2012, I received an unauthorized phone call telling me that in an hour, the Pentagon would be announcing my relief,” he writes. “I was leaving a region aflame and in disarray. The lack of an integrated regional strategy had left us adrift, and our friends confused. We were offering no leadership or direction. I left my post deeply disturbed that we had shaken our friends’ confidence and created vacuums that our adversaries would exploit.”

Obama’s history, but Biden is presently arguing to be the future. This assessment from Mattis makes that argument a lot more complicated, especially since foreign policy and national-security strategy is supposed to be Biden’s strong point. Mattis is now the second former Secretary of Defense to allege that Biden’s the emperor with no clothes on when it comes to his supposed specialty. Remember what Robert Gates wrote about Biden a few years ago?

“I think he has been wrong on nearly every major foreign policy and national security issue over the past four decades,” Gates writes, according to a New York Times review of the book posted Tuesday.

Sounds like a consensus has developed among the people who truly know these policy areas.