One of the most famous aspects of the U.S. Constitution is the system of checks and balances between the three branches of government. The U.S. Congress, also called the legislative branch, has several important powers that keep the executive branch in check. One of the most important checks Congress can exercise upon the executive branch is the power to overturn a presidential veto. A second of these important checks on presidential power is the right of Congress to reject presidential nominations to posts in the Cabinet and Supreme Court.

Presidential Veto

The president has the power to either reject or approve bills passed by Congress. Before a bill becomes a law, the president has 10 days to either approve it by signing it into law, or reject it through a veto. Typically, when vetoing a bill the president returns it to Congress with an accompanying message explaining why it was rejected. The first president to veto a bill was George Washington, who rejected the proposal to change the method of apportioning seats in the House of Representatives.

Overturning Presidential Veto

While the president has the right to veto a bill, Congress in turn has the power to override the president's veto. To do this, two-thirds of both the House of Representatives and the Senate must vote in favor of the override. Getting two-thirds of Congress to vote in favor of a bill is no easy task, so this power can only be exercised in support of an extremely popular bill. In the history of the United States government, fewer than 10 percent of presidential vetoes have been overturned by Congress.

Presidential Nominations

One of the most influential functions of the president is to nominate Supreme Court justices and appoint members to the Cabinet. Because of the wide-ranging powers and influence of the Cabinet and Supreme Court on all aspects of society, the ideologies of the individuals who occupy these posts are of extreme importance. Presidents typically try to nominate persons with whom they share certain philosophies, and can therefore use these positions to further advance their agenda.

Rejecting or Approving Presidential Nominations

Because the power of nomination is such an essential power of the president, the Senate's power to reject or approve those nominations is equally important. When the president nominates a justice or member of the Cabinet, a Senatorial committee reviews the nominee and then makes its recommendation. Based on this recommendation, the whole of the Senate next votes on whether to approve or reject the nominee. Historically, the Senate has rejected about 20 percent of presidential Supreme Court nominees.