Article One, Section One of the Constitution vests “all legislative powers” in Congress. The sovereign power to make laws comes from the people, so their representatives—Congress—should make those laws.
It sounds simple enough, but once the federal government started ballooning in size and regulating everything under the sun, that simple understanding had to go. There was too much governing for Congress to handle on its own, so the courts adjusted, allowing a proliferation of government agencies to exercise lawmaking power, within certain guidelines.&
We’ve now apparently gotten to the point, however, that there’s so much governing to do that it’s too much for the government to handle on its own. In a case now before the Supreme Court, Amtrak—the for-profit, quasi-public entity that the federal government has deemed private for these purposes—has been given a part to play in making laws to regulate its competitors in the rail transportation industry.