Answer:
The Veto power
Step-by-step explanation:
The legislative branch has the power to propose a new law that about to be passed in United States. As a form of checks and balances, the president has the power to review this proposal and use the veto power in case the president is disagree with any part of the proposal.
There is a way for the legislative branch to override this veto. But in order to do that, They need to gather the support of 2/3 of the total legislative members. This tend to be really hard since half of the legislative members are more likely belong to the current president's party.