Why is the executive branch of the federal government necessary for a democratic america?

The executive branch enforces laws and makes sure the legislative branch isn't making unfair laws.

The executive branch is in charge of executing and enforcing the laws. Without this principle, we would not able to make things happen and thus we will become stagnated as a nation. The lack of it would also mean that democracy would not be functioning since citizens elect their government officials and they would not be completing their duties. The democracy makes sure that their representatives respect the law, constitution, and will of people.