Seven years in, it’s clear that Obama has forged a legacy of enormous consequence. But the most transformational aspect of his presidency is something liberals never hoped for: as president, Barack Obama’s most far‐​reaching achievement has been to strip out any remaining legal limits on the president’s power to wage war.

Obama’s predecessor insisted that he didn’t need approval from Congress to launch a war; yet in the two major wars he fought, George W. Bush secured congressional authorization anyway. By the time Obama hit the dais at Oslo to accept the Nobel Peace Prize in 2009, our 44th president had already launched more drone strikes than “43” carried out during two full terms. Since then, he’s launched two undeclared wars, and—as Obama bragged in a speech last year defending the Iran deal—bombed no fewer than seven countries.

In 2011, what officials called “kinetic military action” in Libya completed the evisceration of the War Powers Resolution by successfully advancing the theory that if the U.S. bombs a country that can’t hit back, we’re not engaged in “hostilities” against them. In the drone campaign and the current war with ISIS, Obama has turned a 14‐​year‐​old congressional resolution targeting al‐​Qaeda and the Taliban into a blank check for endless war, anywhere in the world. Last year, the army chief of staff affirmed that finishing the fight against ISIS will take another “10 to 20 years.”

The issue that first animated Obama as an undergraduate was “the relentless, often silent spread of militarism in the country,” as he wrote in an article for the Columbia University Sundial as a college senior in 1983. In “Breaking the War Mentality,” Obama worried that the public’s distance from the costs of war made resisting it “a difficult task,” but a vital one of “shifting America off the dead‐​end track” and undoing “the twisted logic of which we are today a part.”

“It was his first expression of his views on any foreign policy subject,” James Mann writes in The Obamians, his 2012 account of national security decision‐​making in the Obama administration. “And years later, his aides felt it was deeply felt and lasting.”

Yet, as president, instead of “breaking the war mentality,” Obama has institutionalized it.

Will history judge Obama harshly because of that? Probably not. When it comes to presidential legacies, history has lousy judgment.

With the exception of Lyndon Johnson, whose presidential standing has suffered because of Vietnam, waging war rarely hurts a president’s historical reputation. In fact, it usually helps.

Obama needn’t fret too much about getting short shrift from historians. Not only has he been the sort of warrior president too many of them love, but by relentlessly expanding presidential war powers, he’s also empowered the presidents to come.