The Senate's attempt to repeal the Affordable Care Act narrowly failed due to a surprise defection by Sen. John McCain
Before she became Vice President, Kamala Harris was the first South Asian-American woman elected to the Senate
Under the direction of President John Adams, the Congress passed the Sedition Act of 1798, which made it a criminal offence to publish statements critical of the federal government. The first individual to be tried under the law was Rep. Matthew Lyon, who unsurprisingly had voted against its passage. Lyon was re-elected from jail.
In 1949, U.S. Senator Hubert Humphrey called for the abolition of the filibuster in order to advance civil rights bills; as Senate Majority Whip, he advanced civil rights bills; as a Senator in 1975, he voted to lower the threshold to break a filibuster from 67 votes to 60.
In America's first use of the Presidential veto, George Washington vetoed legislation affixing the size of the House of Representatives at 120 members.