Impeachment is governed by Article II Section Four of the U.S. Constitution, which states that the President shall be removed from office on impeachment for and conviction of treason, bribery or other high crimes and misdemeanors. Treasons is levying war against the United States, or in adhering to their enemies, giving them aid and comfort. Bribery is defined in federal statutes, not in the constitution. High crimes and misdemeanors likewise is defined by looking at old British case law, there is no definition in our constitution. And yes, a sitting president can be impeached for things done before being sworn in.
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Impeachment applies to the President, Vice President, and can, and has, been used to remove senators, congressman, federal judges and other “civil officers.” Remember Vice President Spiro Agnew? He avoided a near impeachment, and resigned instead in 1973. Agnew was later indicted for things done when he was governor. An impeachment is an indictment.
Members of the House of Representative (congressmen and congresswomen) bring the charges and the Senate sits as a jury and decides whether to convict or acquit. The Chief Justice of the Supreme Court conducts the trial if a president is facing impeachment, in all impeachments the Vice President presides.
The actual prosecutor who brings witnesses before the Senate is someone appointed to the job by the House of Representatives from its own members. If a President is impeached (brought to trial) he can select his own counsel, or represent him/herself. Removal from office is all that can be done and no jail or fines can be levied, unless the Senate wants to do such. There is no clear rule on how many votes are needed to impeach in the House of Representatives, nor to convict in the Senate, but historically it has been a simple majority vote.
In any federal or state criminal trial, the proof must be beyond a reasonable doubt, but that is not the standard in an impeachment trial. The constitution is silent on the standard of proof needed to convict, the Senate has voted on the question in the past but lets each individual Senator decide if the proof is sufficient even if it is less than beyond a reasonable doubt. If all this sounds like there are no clear rules it is because there are no clear rules. Defining high crimes and misdemeanors can and is not defined in the Constitution. Maladministration, whatever that is, has been derided by writings in the federalist papers, but no definition has been agreed upon. Think in terms of acts that undermine the legitimacy of government, such as abuses of public trust, as well as bribery and treason. The right to remain silent does apply to a president on trial, which means he has all his Fifth Amendment rights as a citizen. As to punishment, removal from office is not required and the Senate can prescribe a lesser punishment. Does all this seem somewhat lacking in form and substance? Can it be a political? Yes. Can it be personal? Yes. It all comes down to the character and ethics and historical perspective of those elected to the House of Representatives and the Senate.
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