The United States has a leader called the President who is chosen by the people every four years. The President's job is to make important decisions about the country and to lead it in good directions. The President has to work with many other people and groups to make these decisions. One of the most important groups that the President has to work with is called Congress.
Congress is made up of two parts: the Senate and the House of Representatives. There are 100 Senators in the Senate and 435 Representatives in the House. They work together to make laws for the country. The President can't make laws by himself, but he can ask Congress to make laws that he thinks will help the country.
Sometimes the President and Congress don't agree on things, and this is called a "split government." This means that the President is from one political party and the majority (or more than half) of Congress is from another political party. When this happens, it can be difficult for the President to get his ideas turned into laws because the members of Congress might not support him.
If the President's political party has control of Congress, it makes things easier for the President. When the President and Congress are from the same political party, they are often more likely to agree on things and work together to make laws. This is called a "united government" because the President and Congress are working together.
In summary, the President and Congress work together to make important decisions about the country. If they are from the same political party, it is easier for them to work together and make laws. If they are from different political parties, it can be harder for the President to get his ideas turned into laws because not everyone in Congress might support him.