Question

A president executive order is based on authority given by congress or ___.

Answer 1

The answer for your question is The Constitution

Answer 2

The Constitution is you're answer

while they were writing the Constitution, they wanted to make the president strong (not-a-figure-head), but not too strong that it becomes a dictator, and so the power is split into 3 (to ensure that no branch becomes stronger over the other), and that most positions have to be changed over the years

hope this helps