President Obama could surprise the country by axing his former counterterrorism adviser, explaining that under Brennan's management, employees broke laws and undermined the separation of powers core to our democracy. Obama may well make a good-faith effort to act in the national interest. But it's impossible to believe that he won't be aware of the following: No U.S. official knows more than Brennan about Obama's many drone killings. Some of the killings were solidly grounded in international law. And others may have violated the Fifth Amendment, international law, or the laws of war.