How does the legislature check the power of Executive organ of government in a persidential system

In the United States, the legislature can impeach and try the President, with resulting removal from office. (This has never happened, but the process did lead to the resignation of Nixon). It can override his or her veto, and must ratify treaties and approve cabinet and judicial appointments.

Congress and state legislatures can also amend the Constitution, regardless of the wishes of the President.