Answer:
These presidents have sent troops to resolve conflicts overseas without waiting for the Congress to declare an official act of war first.
Step-by-step explanation:
The president can only declare war on another country with congressional authorization. To do so without this endorsement is considered a liability crime under national law - and this type of crime can lead to impeachment.
Under the law the president cannot "declare" war, send topas abroad except in cases of foreign invasion or aggression, or make peace without authorization from the National Congress. From this we can conclude that presidents can send troops to resolve conflicts abroad without waiting for Congress to first declare an official act of war, that is, they can only send troops on a peace mission.