In the United States, a bill becomes law only when it has passed both houses of the legislature and been signed by the executive. According to Vote Smart, the process from proposal to passage is complicated, but procedures are similar in both chambers of Congress.
According to Vote Smart, any member, in either chamber, may introduce a bill. In the House of Representatives, the bill is accepted by the Speaker of the House, and in the Senate, the bill is accepted without objection by the Senate's presiding officer. Once accepted, the bill is sent to the relevant committee, and copies of the proposed measure are printed for distribution. The committee has broad discretion to affect the markup of the bill. The committee may hold hearings, survey the relevant government agencies and refer the proposal to a subcommittee for recommendations. Eventually, the committee marks up the bill and sends it to the floor for a vote. Generally, the bill is open to debate at this stage, and it is eventually passed or defeated. If passed, the bill moves to the opposite chamber of Congress for final passage. The last step in becoming a law is for the bill to be sent to the president, who may sign or veto it. Presidential vetoes may be overridden by a two-thirds majority of Congress.