90 Constitution of the United States, Art. III, Sec. 2, Cl. 3.
Impeachment is the manner of trial fixed by the Constitution for the trial and removal of Federal officers who are accused of treason, bribery, and other high crimes and misdemeanors. Congress alone has the power of conducting an impeachment of Federal officers. The legislature of a State has the power of impeaching State officers. Impeachment, as the word is commonly used, includes both accusation and trial. The "Impeachment" or accusation is brought by a two-thirds vote of the lower house, and the trial and conviction or acquittal is carried on by the upper house. Andrew Johnson, President of the United States, was impeached--i.e. he was formally accused, but he was acquitted in his trial in the Senate. Conviction in an impeachment proceeding causes an officer to be removed from office and disqualified from ever holding any office of honor or trust under the government again. A person may be convicted and not given the full penalty. He may be only removed from office, but not disqualified from again holding office.
It is possible that a crime may be committed on a river that forms State boundaries. Where a river forms a boundary the middle of the main channel is made the boundary line. It is often difficult to determine on which side of the line the crime was committed, and both States may then claim to have jurisdiction over the case. This must be decided as any other fact in the case.
The manner of the trial in use, before jury trial was established, was by ordeal or by battle. In trial either by ordeal or by battle the issue was left to God to decide and He was thought to perform a miracle to reveal the guilt or innocence of the accused person. One form of ordeal was to compel the accused to plunge his arm into boiling water and if innocent the Lord would protect him from being scalded. Another form of ordeal was to compel the accused to walk barefoot over hot plow shares. If innocent the Lord would again protect his feet from being burned.
The first form of jury to displace the old ordeal or battle as a means of deciding guilt or innocence was the "compurgators" or "oath bearers". They comprised a group of men who would appear before the court and give oath that the accused was not a bad man and had committed no crime. They did not investigate the accusation, they only testified to the good character of the accused. If a man accused could not produce compurgators, he must undergo the ordeal. The duty of these oath bearers gradually became more extended until they became investigators, and finally became a grand jury.