They can override (overrule) a veto, or a canceling of something that allows the president to check the power of congress.
The veto is a way in which the president can check the power of the legislature.
The Congress and the Supreme Court provide a constitutional check on the President's powers
The President checks Congress when he vetoes a bill
Power was given to Congress in order to make sure that power was not concentrated on the President alone. Congressional power is a check on the president's power.
Veto
vetoing bills
By the power of the veto.
Both the Legislative (Congress) and the Judicial (Supreme Court), have the power to keep the President's power in check.
the president has the power to check congress through thepower of vetoing legislation that comes to his desk.
i dunnobarrack obama man
veto
The president can reject a proposed law through veto.