“An impeachable offense is whatever a majority of the House of Representatives considers it to be at a given moment in history.” Gerald Ford, 38th President of the USA.
Before the circus earlier this year, only two American presidents had been impeached. In 1868 Andrew Johnson endured the process for allegedly illegally removing Secretary of War Edwin M. Stanton. Bill Clinton was impeached in 1998 for allegedly lying under oath to a federal grand jury and obstructing justice regarding an extramarital affair. Neither was convicted by the Senate. Richard Nixon likely would have been impeached in 1974 for his connection to the Watergate scandal, but he resigned from office. (Pacific Legal Foundation)
When the US Constitution was written and adopted, parliamentary systems were in existence in several locations around the globe, typically to wrench control of the government from a monarch. George Washington refused to be king, so the founding fathers opted to craft the presidential republic we have today.
Congressional terms were set at 2 years, to give “the people” an opportunity to “fix” the lower legislature when dissatisfied. The Senate were given 6 year terms, with the thought that this longer period would add a steadying hand, or otherwise prevent government defaulting to popular whim. The presidential term was set at 4 years, which gave the leader of the government some room to effect progress and set policy (or at least provide enough rope for a proverbial hangman’s noose before the next election).
Constitutional convention participant Roger Sherman suggested “the executive” should be “nothing more than an institution for carrying the will of the legislature into effect.” Charles Pinckney proposed an executive with “vigorous” powers, while James Wilson even stated it would “require the vigor of monarchy.” (Pacific Legal Foundation)
That said, “James Madison argued for an impeachment process, because presidents “might pervert [their] administration into a scheme of peculation (embezzlement) or oppression.” Presidents might even “betray [their] trust to foreign powers.” (Ibid)
In the end, the Constitutional Convention voted to retain impeachment but remained torn regarding what might justify the process. “Malpractice” language became “treason and bribery.” George Mason suggested “maladministration” should be adequate to impeach, but “Madison objected, fearful it would give Congress too free a hand in removing a president for almost any reason.” (Ibid)
Compromise language appears in the ratified Constitution: presidents may be impeached for “Treason, Bribery, or other High Crimes and Misdemeanors.” They chose the words for very specific reasons. “High Crimes and Misdemeanors” is ambiguous enough for Congress to define its precise contours on a case-by-case basis, while also being rooted in British and early American history via past impeachments of public officials. (Ibid)
The Senate would conduct impeachment trials. In Federalist 65, written to explain to the citizens of New York why they should support ratification of the Constitution, Alexander Hamilton argues that the Senate was the best forum for impeachment trials because senators are representatives of each individual state in their sovereign capacity, rather than being directly dependent on the people for reelection. (For the first 125 years of the Republic, senators were appointed by state legislatures. The 17th Amendment changed this system by providing that senators would be elected by the people.) According to Hamilton, senators would be more likely to act impartially in deciding a president’s guilt. (Ibid)
Finally, the Supreme Court itself would not have a direct role in impeachments or impeachment trials, as its members were dependent on the Executive Branch for their nominations. But the third branch was still provided an important role, as the Chief Justice was charged with presiding over the president’s trial before the Senate. (Ibid)
The attempt to remove Donald Trump for this past summer’s phone call to Ukraine has failed, although pundits suggest there will be another attempt over the President’s handling of the Corona virus pandemic.