system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How much power does a US president really have?
gpt
The president has certain powers, which, depending on the relative strength and composition of the legislative and judicial branches, can be quite extensive.

Primarily, however, the president is the head of the executive branch, which means he's in charge of a bunch of powerful federal agencies and departments as well as responsible for carrying out and enforcing laws. The executive branch is huge, and encompasses departments such as Defense, State and the Treasury. The president, while not directly overseeing day-to-day operations, he does appoint department heads, set broad agendas and goals and directs activities. The president also has the power to veto laws passed by congress and issue executive orders (which aren't laws but carry the force of law when issued under proper authority).

All of these powers have checks on them through the other branches. Congress can override vetoes, for example, or the Supreme Court can declare an executive order unconstitutional (or, at least, outside of presidential authority).

It's important to note just how much power executive departments and agencies have. They all report directly to the president and their leaders serve at his pleasure. The Department of State, for example, is in charge of all foreign relations. Or the Department of Homeland Security, which is responsible for all sorts of fun stuff like the TSA or Border Patrol.