Checks and Balances: Checks and balances refer to the system where each branch of government has powers that can limit or check those of another branch, preventing any one branch from becoming too dominant.
Impeachment: Impeachment is a process used by Congress to remove high-ranking officials, including presidents, from office for committing 'high crimes and misdemeanors.'
Subpoena: A subpoena is a legal order demanding someone's presence at a trial or requiring them to produce certain documents or evidence.