Future historians will ask why George W. Bush sought and received express congressional authorization for his wars (against al Qaeda and Iraq) and his successor did not. They will puzzle over how Barack Obama the prudent war-powers constitutionalist transformed into a matchless war-powers unilateralist. And they will wonder why he claimed to “welcome congressional support” for his new military initiative against the Islamic State but did not insist on it in order to ensure clear political and legal legitimacy for the tough battle that promised to consume his last two years in office and define his presidency.
“History has shown us time and again . . . that military action is most successful when it is authorized and supported by the Legislative branch,” candidate Barack Obama told the Boston Globe in 2007. “It is always preferable to have the informed consent of Congress prior to any military action.” President Obama has discarded these precepts. His announcement that he will expand the use of military force against the Islamic State without the need for new congressional consent marks his latest adventure in unilateralism and cements an astonishing legacy of expanding presidential war powers.
But that was different, because they thought there would never be a Republican president again.