The non-legislative powers of Congress include the abilities to amend the constitution, approve presidential appointments, investigate matters that interfere with or impede its legislative duties, impeach officials, and choose a president if no majority winner emerges as the result of an election. therefore, if congress did NOT have these powers the president would have all control over the country, no longer giving the country any rights or giving citizens the right to run loose and break all bills and federal laws having no political structure could bring back wars, deaths and other crimes.
The Constitution also grants the Senate the unique non-legislative power to confirm or deny all major appointments made by the president. The Constitution requires that the president seek the "advice and consent" of the Senate when appointing federal judges, cabinet officers, and major officials of executive agencies."
