President's can't make or enforce laws. Congress makes laws and the Judiciary enforces those laws. Presidents are executives. Their job is to lead. Presidents can have their own agenda, but as some of them have seen, there are times when Congress and the Judiciary can stall them or make them grind to a halt. Or one or the other can help the president.
As an example, to make a long story short, in 1861 President Lincoln suspended habeas corpus, the SCOTUS said only Congress had that authority. President Lincoln did it anyway, and in 1863 Congress passed a law authorizing the president to do it.
Other times, the president doesn't get any help from Congress or the Judiciary. Such as when President Trump tried to end Birthright Citizenship with an Executive Order. That got shot down because Birthright Citizenship is plainly outlined in the 14th Amendment of the Constitution, unlike many other Amendments which are not very clear to many people. Any legal challenges to it as well as the process to create a new Constitutional Amendment could both be lengthy and could take years.