The "deep state" is a web of federal administrative agencies, career politicians, lobbyists, and compliant mass media. It acts as a shadow government that largely sets the nation's political agenda.
The deep state has been around for decades, but is more powerful than ever because the federal government is larger and more intrusive than ever. Most Americans witnessed deep state power for the first time during the Trump administration, when it publicly resisted the authority of an elected president.
One prop of the deep state's power is the 1984 Supreme Court's ruling in Chevron v. Natural Resources Defense Council (pdf). That ruling is called the "Chevron doctrine." On May 1, the justices granted certiorari in (that is, agreed to review) a new case in which they may overrule the Chevron case and its "Chevron doctrine."
The 'Deep' Background
The Constitution created a democratic federal republic. It instituted an elected Congress to make laws, an elected president to enforce laws, and an appointed judiciary to resolve disputes under those laws.
In addition to empowering the new government, the Constitution also limited it. The Constitution included some specific exceptions to federal authority, such as the first eight amendments in the Bill of Rights. It also reserved most governmental functions to the states, a reservation encapsulated in the Ninth and Tenth Amendments.
People who wield power are seldom happy with limits on their power. Federal officials and those who cater to them always pushed back against the Constitution's limits. Those limits began to fall in earnest during the late 1930s and early 1940s. Instead of resisting the assault, liberal majorities on the Supreme Court "reinterpreted" the Constitution to accommodate the assaulters. I described the court's decisions during that era in my Epoch Times series, "How the Supreme Court Re-Wrote the Constitution."