Regarding the Twenty-Third Amendment §1's "shall appoint in such manner as the Congress may direct", one must also consider §2 which states:
The Congress shall have power to enforce this article by appropriate legislation.
Q: Could Congress veto the NPVIC via its control of DC's electoral votes?
But Congress is not a party to the NPVIC, and thus the Compact does not bind them. It's quite easy to imagine the ... new Congress decid[ing] to revoke DC's home rule charter and pass legislation awarding DC's electoral votes to the candidate from their preferred party.
Due to changes in the Electoral Count Act, the new Congress is prevented from changing much of anything. There would be no need to "revoke DC's home rule charter". Congress could simply revoke D.C.'s agreement to the National Popular Vote Interstate Compact (NPVIC).
Any change by the new Congress directing the District to appoint electors (directly or indirectly) for a particular candidate could (and likely would) be challenged as "not appropriate". See, Consent for NPVIC, below.
Consent for NPVIC
Or, more realistically: what if the members of the NPVIC including DC have only a bare majority of 270 electoral votes combined, but then the day before election day, Congress withdraws DC from the Compact?
(The "day before election day" (November) is before the electoral votes are counted (December) though the electoral vote count is often known soon after election day. I will assume the December Electoral College date.)
It would, somewhat, depend on whether the NPVIC had previously received the consent of Congress.
Article I, Section 10, Clause 3:
No State shall, without the Consent of Congress, ... enter into any Agreement or Compact with another State, ...
The Constitution does not dictate the timing or manner in which Congress must consent to a compact. The Supreme Court has interpreted the Constitution’s silence to mean that Congress may use its wisdom and discretion to choose how and when it gives consent. In an 1893 case, the Supreme Court stated that Congress ordinarily should provide authorization before the states join and carry out a compact, but Congress may consent later if the compact addresses an issue that is best considered after its "nature is fully developed[.]" The Court has further explained that Congress can consent to a compact either in advance or by giving approval after the states already negotiated and joined the compact.
If Congress had consented to the NPVIC, there is little that can be done because the rules for appointing electors must be in place before election day.
( 3 U.S. Code § 5(a)(1) )
If Congress has not consented, Congress could deny consent before the general election. After the general election and before the meeting of the Electoral College, it is problematic whether denial or litigation would be effective. Congress would need to claim diminished federal sovereignty.
In the context of interstate compacts, however, the Supreme Court has adopted a functional interpretation in which only compacts that increase the political power of the states while undermining federal sovereignty require congressional consent.
The authors of the NPVIC argue strenuously against the possibility of a single state vetoing the NPVIC by attempting to withdraw. They point out that the compact as written prohibits this ...
If it's "quite easy to imagine" what Congress may do, it is also quite easy to imagine what the District may do.
In the case where,
the popular vote is for the Republicans and
the Electoral College vote is for the Democrats and
the popular vote margin is less than the margin for the District of Columbia,
one might expect that D.C. would renege because the votes for Democrats in the District are often greater than 80%. Refusing to honor the NPVIC would ensure a Democratic victory in keeping with the politics of the District. (The margin in California is much greater and votes for Democrats are often greater than 60%.)
In the 117th Congress, some bills related to this issue were introduced.
Some Democrats introduced bills —
H.J.Res.14 – Proposing an amendment to the Constitution of the United States to abolish the electoral college and to provide for the direct election of the President and Vice President of the United States.
S.J.Res.69 – A joint resolution proposing an amendment to the Constitution of the United States to abolish the electoral college and to provide for the direct election of the President and Vice President of the United States.
Some Republicans introduced bills —
H.J.Res.19 – Proposing an amendment to the Constitution of the United States to repeal the twenty-third article of amendment to the Constitution of the United States.
S.J.Res.18 – A joint resolution proposing an amendment to the Constitution of the United States to repeal the twenty-third article of amendment to the Constitution of the United States.
