Mitt Romney was the only Republican member of the Senate to find the president guilty of abuse of power.
It came after a trial overseen by U.S. Supreme Court Chief Justice John Roberts.
Romney is a former Massachusetts governor and was elected to the Senate in 2018 from Utah.
He was also the Republican presidential nominee in 2012.
You can watch Romney's February 5 speech below.
Below, you can see how Trump has reacted Twitter.