Sen. Ron Wyden has spent two years demanding that the Obama administration share its legal opinions justifying the targeted assassinations of suspected American terrorists abroad. After all, as a member of the Intelligence Committee, the Oregon Democrat is entitled (and cleared) to know. How can his panel provide oversight if officials won’t say what legal authority they have, let alone in which countries it applies? The White House has spent those two years stonewalling. “The administration’s position is basically, ‘Trust us,’” Wyden tells National Journal. “Nowhere in the charge to the committee does oversight get defined as trusting the executive branch of the United States.”

In part, Wyden is just a recent victim of a shift in constitutional power that has been going on for decades, back to when President Truman ordered forces into Korea without congressional approval. But today’s covert war—in which spies and soldiers kill people without trial—establishes new terrain somewhere between military and intelligence activities. Here, the executive branch feels compelled to protect its security interests at the same time that Congress has the constitutional power to declare and oversee war. And rather than explain why it considers its tactics legal even off the battlefield, the White House simply claims authority to do as it pleases under the Authorization of Use of Military Force passed by Congress after the Sept. 11 attacks. “Without real public accountability,” says former Rep. Lee Hamilton, a cochairman of the 9/11 commission who now directs Indiana University’s Center on Congress, “the president has the power to kill people any time, based on a secret process. That, as far as I’m aware, is unprecedented.”

President Obama’s refusal to declare or explain his legal right to kill follows White House tradition. According to reports, President Clinton secretly authorized the assassination of Osama bin Laden, his lieutenants, and possibly even unconnected people.