The process for dealing with a President or other federal elected official who abuses their office is spelled out broadly in the Constitution.
In Article I of the Constitution, it says the House shall have the sole power of impeachment and the Senate shall have the sole power to try impeachments.
But the process has evolved over the years. The Constitution does not include the term “articles of impeachment,” but a November 2019 Congressional Research Service analysis of the impeachment process explains what they are.
“The House impeaches an individual when a majority agrees to a House resolution containing explanations of the charges,” according to the report. “The explanations in the resolution are referred to as ‘articles of impeachment.’”
Once articles of impeachment are approved in the House, the Senate takes those allegations and conducts a trial considering whether to remove a President from office. The Constitution mandates that the chief justice of the Supreme Court presides.
A President may be impeached and removed for “Treason, Bribery, or other high Crimes and Misdemeanors,” according to Article II of the Constitution. There’s no hard and fast definition of those, so Congress has the ultimate say.
Democrats initially prepared two articles of impeachment against Trump, for abuse of power and obstruction of Congress. They will debate those and then proceed to a vote before their holiday recess.
They’ll vote on each one separately, first in the House Judiciary Committee and, if majorities approve them there, in the full House. It takes a simple majority to refer an article of impeachment to the Senate. It’s a much higher threshold – a 2/3 supermajority, or 67 senators – to remove a President from office.
Articles of impeachment against Bill Clinton
In the case of President Bill Clinton, the House Judiciary Committee prepared four articles of impeachment in 1998. But only two – for perjury and obstruction of justice – were referred by the full House over to the Senate for trial. Multiple Republicans broke ranks to oppose the other two, which accused perjury in a deposition and abusing power in his efforts to cover up his relationship with Monica Lewinsky. A number of Republicans, including Sen. Susan Collins of Maine, who is still a senator, sided with Clinton to allow him to stay in office.
Articles of impeachment against Richard Nixon
President Richard Nixon resigned in 1974 before the House could vote to impeach him, but after the House Judiciary Committee, with help from six Republicans on the committee, had approved three articles of impeachment – for obstructing justice, violating the rights of citizens, and obstructing Congress’s power of impeachment.
This last article is similar to the obstruction of Congress article Democrats prepared against Trump.
Articles of impeachment against Andrew Johnson
The case of President Andrew Johnson in 1868 went differently. Congress was at odds with him over Reconstruction and had passed a law – the Tenure of Office Act – in an effort to essentially restrict Johnson’s power. They impeached him for ignoring the law they had just passed.
The House prepared and passed 11 articles of impeachment against Johnson and most of these had to do with the Tenure of Office Act. The trial went on for months in the Senate. A majority supported removing him from office, but senators fell one vote short of a 2/3 necessary after a number of Republicans sided with him.
So Johnson was acquitted by the Senate first on the 11th article and then, according to the House historian, on two more articles. The Senate ultimately abandoned the trial.