Congress cannot directly compel states to enforce federal regulations or take certain actions. Instead, Congress often uses indirect methods, such as offering incentives or attaching conditions to federal funding, to encourage states to adopt certain policies or regulations.
They can set certain requirements if the states wish to participate in the federal election.
like adhering to federal law by insuring only LIVING citizens vote and vote ONCE in their HOME district and not in any other state.
“Congress cannot directly compel states to enforce federal regulations or take certain actions.”
The following is exerpted from https://constitution.congress.gov/browse/essay/artIV-S4-3/ALDE_00013637/
ArtIV.S4.3 Meaning of a Republican Form of Government
“Article IV, Section 4:
The United States shall guarantee to every State in this Union a Republican Form of Government, and shall protect each of them against Invasion; and on Application of the Legislature, or of the Executive (when the Legislature cannot be convened) against domestic Violence.”
Although the Supreme Court has generally avoided addressing Guarantee Clause questions because of their political character,1 it has occasionally ruled on the merits of such challenges. These decisions, as well as contemporaneous sources, shed some light on the meaning of the Republican Form of Government guaranteed by the Clause.2 For example, in the Federalist No. 39, James Madison emphasizes popular sovereignty and majoritarian control as among the distinctive characters of the republican form...
Kriskrinkle comment: Seems to me that if “popular sovereignty and majoritarian control (are) among the distinctive characters of the republican form”, then something can be done to ensure popular sovereignty and majoritarian control as opposed to cheating by a minority.