The main purpose of Congress is to check on presidential powers. Only Congress can declare war, the Senate must approve treaties, and also decide on the president’s nomination for ambassadors and cabinet members. Congress can increase or decrease foreign aid, or the budget for defence projects. They can also set a time limit for US troops that are deployed. Congress has used its power in the past, to limit executive power. The War Powers Act of 1973, as a result of the Vietnam War, required Congress to be consulted before the president sends US troops to war. This puts a 60-day limit of their deployment, if congress does not