This (somewhat widespread) myth stems from a failure to realize that citizens of the District of Columbia already have been able to vote for President and Vice President since ratification of the 23rd Amendment in 1961. The District has three electoral votes.
The 23rd Amendment specifies that presidential electors representing the District of Columbia:
“shall be considered, for the purposes of the election of President and Vice President, to be electors appointed by a state.” [Emphasis added]
The National Popular Vote compact is consistent with the 23rd Amendment in that it treats the District of Columbia as a “state” for the purposes of presidential elections. The compact adds up the popular vote from all 50 states and the District of Columbia to determine the national popular vote winner.
The Council of State Governments (CSG) lists 17 major interstate compacts to which the District of Columbia is a party. Examples include the Interstate Compact on Juveniles and the Interstate Compact on the Placement of Children (both of which are compacts to which all 50 states and the District of Columbia belong). The Interstate Compact for Education encompasses 48 states, including the District of Columbia.
The District of Columbia approved the National Popular Vote compact in 2010.
Prior to 1973, it was customary for Congress to enact interstate compacts on behalf of the District of Columbia.
However, in the District of Columbia Home Rule Act of 1973, Congress delegated its authority to pass laws concerning the District to the Council of the District of Columbia in all but 10 specifically identified areas listed in section 602(a) of the Act.