In theory, only Congress can make a law. But Congress of late has eroded its own legislative monopoly. The Affordable Care Act, to take one example, is not so much a legislative program as an enabling act, a vast collection of “the secretary shall”s that amounts to the legislative branch’s asking the executive branch to come up with a law so that Congress does not have to. Congress sometimes delegates its legislative powers intentionally, and sometimes it sits quietly while the executive branch simply arrogates congressional powers to itself, as the Environmental Protection Agency has done under the Clean Air Act. This happens in part because Congress is timid and lazy, disinclined to do the hard work of legislating — especially when there is no political incentive to do so. It also happens because Congress frequently likes the results: If the EPA enacts policies that congressional Democrats want to see enacted and saves them the difficulty of facing voters who disapprove of such policies, so much the better. The EPA is not up for reelection every two years. Or ever.
Members of the legislative branch understand that voters have limited spans of attention, a fact that may equal presidential ambition as a force behind our ever-more-imperial and ever-more-imperious executive. The presidency is relatively easy to follow: There’s just the one guy (how many Americans could name the complete Cabinet?), whereas there are hundreds of people in Congress, and all those committees and subcommittees, reconciliation, procedural votes, etc. In a sense, all eyes are on the presidency for the same reason that the Twilight books outsell the works of William Shakespeare or James Joyce: Compared to the 535 members of Congress and the seemingly endless permutations of them, one man is a neurologically bite-sized morsel.