There is just one real check on the president — impeachment — and it is political, not legal.
The United States has the world’s oldest constitutional democracy, one that has survived the test of time and given birth to perhaps the most successful society in human history. What sets the nation apart is not how democratic it is, but rather the opposite. U.S. democracy has a series of checks intended to prevent the accumulation and abuse of power by any one person or group. But there is one gaping hole in the system: the president.
Our "laws" represent decisions that follow the debate and discussion, the controversy and conflict, that is the essence of "politics." We make "political" decisions about what we want to do, and if we follow our own prescriptions, we quite often accomplish what we have said we want, and what our "laws" tell us is our objective.