Unconstitutional through and through. The Constitution permits states to set their own election laws, regulations, and processes. SCOTUS would throw out the ‘RATS illegal bill.
The states can set their own rules for state and local elections but the Feds can control how the federal elections can be run. Many states (Virginia is an exception) just run their elections concurrent with the feds as a convenience. The states can can counter by saying...okay...we won’t use state resources or people to help you feds with “your elections”.
The state elections for the state legislatures can then be protected so that the legislatures still would have to sign off on the electors that get sent for the Presidential election years.
The US constitution allowed for states’ control of elections but they included a vague line about congress being able to make subsequent rules about how the elections should be conducted. That is how the Dems are justifying the complete federalization of all elections. Yet this same clause doesn’t allow the complete take over of all state and local elections processes. It could lead to many states separating the two elections and telling the feds to fund their own elections and to get their own people and voting precincts. What a pickle for congress!