Lee Drutman writes:
"[O]ver the years, and particularly over the past few decades, Congress has ceded more and power to the executive. Admittedly, it has done some of this willingly. After all, better to delegate away hard decisions to the bureaucracy, which you can always then blame if something goes wrong, But willingly or unwillingly, the effect is the same. More and more policy has been made in the executive branch. And more and more power (especially in national security) has gone unchallenged.
"At the most basic level, it’s a numbers game. The executive branch has tens of thousands of people making policy, across multiple agencies. Congress has fewer and fewer. Below, take a look at staffing levels of members’ offices in Washington. Over the past several decades, members of Congress have employed fewer and fewer people in Washington, where policy is made. Some of this decline is a result of shifting staff to district offices; some of it is a result of flat or declining budgets. But the result is the same. Members have fewer policy staff to help them."