Congress is the branch of the U.S. government that writes laws and controls the money. Here’s how its two chambers work, and why getting anything passed can be so hard.
The U.S. Constitution splits power between three branches: Congress makes the laws, the president carries them out, and the courts interpret them. Congress is made up of two chambers with different jobs and very different rules.
The House of Representatives has 435 voting members. Each represents a district of roughly similar population, so bigger states like California and Texas have many more members than small states. House members serve two-year terms, so every seat is up at every federal election. The House is led by the Speaker, who is chosen by the majority party.
The Senate has 100 members, two from every state regardless of size. Senators serve six-year terms, with about a third elected every two years. The Vice President is the Senate’s president and can cast a deciding vote in a tie, while the majority leader runs its day-to-day business.
How a bill becomes law
A bill must pass both the House and the Senate in exactly the same form. The president can then sign it into law or veto it. Congress can override a veto, but only with a two-thirds vote in both chambers, which is rare.
The biggest hurdle is in the Senate. Under its rules, senators can delay a vote indefinitely, known as a filibuster, unless 60 senators agree to end debate. That means most major legislation needs support from both parties.
There are exceptions. Some budget and tax bills can pass with a simple majority through a process called budget reconciliation, which is how Republicans passed Trump’s major tax and spending bill, the One Big Beautiful Bill Act, in 2025.
Other powers, and why shutdowns happen
The two chambers also have their own special powers. The House can impeach a president or other officials, which works like laying charges. The Senate then holds a trial, and a two-thirds vote is needed to remove someone from office.
The Senate confirms the president’s nominees, including cabinet secretaries, ambassadors and federal judges, and must approve treaties by a two-thirds vote.
Congress also controls the government’s purse strings. If it fails to pass funding bills on time, parts of the federal government shut down, and many workers are sent home or work without pay. The shutdown that began in October 2025 lasted 43 days, the longest in U.S. history.
Because both chambers must agree, the balance of power matters. When different parties control the House and Senate, or Congress and the White House, very little legislation tends to get through.
