Impeachment and removal are different decisions
The Constitution gives the House of Representatives the sole power of impeachment and the Senate the sole power to try impeachments. An impeachment by the House is therefore an accusation, not itself a removal from office.
A simple House majority can approve an article of impeachment. Conviction in the Senate requires two-thirds of senators present.
The Senate's role creates a high removal threshold
When the president is tried, the Chief Justice presides. Senators determine guilt on the articles transmitted by the House, operating under the constitutional threshold for conviction.
This division deliberately distributes the process between two institutions rather than allowing one chamber to remove an official by itself.
Disqualification is a separate consequence
The Constitution permits judgment in impeachment cases to extend to removal and disqualification from holding federal office, while leaving the person subject to ordinary criminal law where applicable.
Because impeachment is a constitutional political process rather than a criminal prosecution, its standards, actors and consequences are distinct from those of a criminal court.