This is something I don't think I've ever heard the Democrats propose - a national standard for handling votes.
Unconstitutional.
Article 2 said:
The Congress may determine the Time of choosing the Electors, and the Day on which they shall give their Votes; which Day shall be the same throughout the United States.
plus
10th Amendment said:
The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.
equals no ability for the federal government to set state voting standards.
Anything arising from OTHER amendments, such as the 12th, 14th, 15th, 19th, 24th, or 26th all meet the requirements of the 10th. Things like the Voting Rights Act are predicated on the unproven notion that state voting laws were intentionally written to exclude people, in violation of a constitutionally-protect human right.
But, the federal government has no authority to establish state voting standards outside of the constitutional authority stated above.