Comment by terminalshort

It's been the established president since the Korean War when the US began ignoring the constitutional provision that gave congress the power to declare war. Additional examples are the Vietnam War, Serbia, Afghanistan, Iraq I & II, the Libyan regime change, and the current Iran conflict, and there are plenty more. The written law still states that the president does not have this power, but the actual unwritten law has been that he can. And that is the only law that matters.