Casey Burgat at R Street:

The legislative branch simply does not have the levels of staff resources, funding or expertise to conduct effective oversight of the executive branch, including—and perhaps even especially—on matters of foreign affairs, intelligence and national security. Congressional committees are supremely overmatched by the resources of the executive agencies they are tasked with overseeing, and as a result, they cannot reasonably keep up with the decisions, plans and results produced by the sprawling military bureaucracy. This dynamic is compounded by the reality that the president enjoys near unilateral authority over military and intelligence operations, ultimately leaving Congress with little insight into the day-to-day operations of the people, programs and agencies they are expected to oversee and fund. Instead of providing an independent check on the president’s military authorities through oversight, such a lack of capacity has rendered Congress dependent upon the information provided by the very agencies they monitor.