Final answer:
If Congress adjourns before the ten-day period for Presidential action on a bill is up and the President does not sign the bill, it does not become law, a process known as a "pocket veto." This is a legislative power that serves as a check on Congress. Without an appropriations bill or continuing resolution, a government shutdown may occur.
Step-by-step explanation:
When Congress sends a bill to the President for approval, there are several actions the President can take. If the President signs the bill, it becomes a law. If the President does not sign or veto the bill, it automatically becomes law after ten days, excluding Sundays. However, there's a special situation called a "pocket veto".
If Congress adjourns during the ten-day period and the President does not sign the bill, the bill does not become a law. This is because the President's opportunity to return the bill with objections (veto it) is effectively eliminated due to Congress not being in session. In other words, because Congress has adjourned, they cannot override the veto, and thus, the bill fails to become law. This aspect of legislative powers is an important check in the balance of power between the legislative and executive branches of the United States government.
It's also important to note that if Congress and the President cannot agree on a budget, a government shutdown may occur. This happens if Congress does not pass an appropriations bill, also known as the budget, and there is no continuing resolution in place.