Former Defense Secretary Robert Gates has been on a tear denouncing his most recent commander-in-chief, President Barack Obama.

His latest salvo came last week in a blistering op-ed in the Washington Post. Gates painted a picture of what our next president must be simply by listing, bullet point by bullet point, everything that Obama is not.

The next president, according to the Gates opinion piece, must understand the form of government we have and the need to build coalitions with the other two branches of government to get things done.

He or she needs to speak truthfully to the American people, not spin everything; must be resolute, not draw red lines without the firm intention of backing them up; must be a pragmatic problem solver, not an agenda-driven ideologue like our, ahem, most recent presidents; and must be restrained, in rhetoric and in his or her attitude toward the other branches of government.

‘The anti-Obama’

Above all, according to Gates’s conclusion, the next president must be a unifier of the country and restore civility to the political process.

It’s a tall order, and probably less a realistic description of who will win next November than a critique of the current president and, to a certain extent, his predecessor.

Gates knows both firsthand because he was appointed Pentagon chief by President George W. Bush in 2006 and stayed on it that position well into Obama’s first term, stepping down in July 2011.

His thinly veiled critique comes as many express frustration over a lack of leadership from a lame-duck president who seems more preoccupied with checking off boxes in his “legacy” agenda — Pacific trade deal, Iran nuclear deal, any sort of climate-change deal (regardless of how meaningless) — than in putting out the fires of successive crises abroad.

This frustration culminated in widespread criticism of Obama’s prime-time address Sunday on terrorism, which, clocking in at 13 minutes and coming four days after the San Bernardino, Calif., shootings, seemed to many to be too little, too late.

The Boston Herald editorialized about “Obama’s tired script,” while USA Today columnist James Robbins said “the president doubles down on failure.”

Gates has been particularly acerbic. Last week’s op-ed follows an October missive in which he refrained from criticizing Obama by name but quoted with withering sarcasm some of the president’s more sophomoric put-downs of foreign-policy critics. (The online version helpfully provides links to the president’s speeches.)

In the October op-ed, co-authored with former Secretary of State Condoleezza Rice, Gates insisted that a no-fly zone in Syria, as recommended by the authors and many others (including Democratic front runner Hillary Clinton), is not a half-baked idea, as Obama dismissively labeled it.

Nor is recommending stronger support for Kurdish rebels, Sunni tribes, Iraqi special forces and other potential allies “mumbo-jumbo,” as Obama characterized this type of suggestion.

Yet none of the declared candidates in either party so far fulfills all of Gates’s bullet points for the next president.

For all of former Secretary of State Clinton’s experience and grasp of government, she so far has not been the unifier Gates is looking for. Bernie Sanders’s floundering in the areas of foreign policy and terrorism has exposed the narrowness of his appeal.

John Kasich, the Ohio governor who is the thinking Republican’s favored candidate, has come across as too bland or too petulant in his debate appearances. New Jersey Gov. Chris Christie might be resolute and likes to tout his ability to work with a Democratic legislature, but his confrontational style hardly makes him a unifier.

The freshman senators in the Republican field — Marco Rubio of Florida, Ted Cruz of Texas and Rand Paul of Kentucky — would be far too prone to the amateurism that Gates implicitly criticizes in Obama.

Gates may be just one former official. But he served two presidents of different parties in the third-ranking cabinet department and is, literally, a Boy Scout (Eagle Scout in his youth and now president of the Boy Scouts of America). He’s held in high regard on both sides of the aisle.

In his long career of public service, Gates has reaped his share of criticism, especially for his time as deputy director and then director of the CIA under Presidents Ronald Reagan and George H.W. Bush.

If nothing else, however, his experience in intelligence, on the National Security Council and as head of the Pentagon makes him one of the most seasoned analysts of foreign policy and national security that we have. So when he suggests we need someone as our next president with different qualities of leadership than those possessed by Barack Obama, it bears listening to.