The Congress, or Legislative Branch of government, can check the power of the Executive Branch in many different ways. Some examples of congressional checks include [1] approving presidential appointees to cabinet positions or courts (including the supreme court) [2] override presidential vetoes with a 2/3 vote in each chamber or [3] the power to declare war. The executive is the commander and chief of the armed forces but cannot unilaterally declare war without congressional approval as stated in the Constitution. There are other examples as well, including treaty ratification and control of the government budget (sometimes called the 'power of the purse').
