Why does congress have to approve dc laws?

Congress must approve laws passed by the District of Columbia because the U.S. Constitution grants Congress ultimate authority over the federal district. This oversight is rooted in the Constitution's Article I, Section 8, which gives Congress the power to exercise exclusive legislation in the District. As a result, local laws enacted by the D.C. Council are subject to congressional review and can be disapproved within a certain timeframe. This system reflects the unique status of D.C. as a federal district rather than a state.