John, you said:

In a move that could set a disastrous precedent, the Republican Governor and Democratic Secretary of State of Mississippi have come together to ask that a federal judge rule that the state legislature must enact a voter ID law.

(id. emphasis added). That does not sound even close to legal.

The separation of powers doctrine says that the administrative branch of a state cannot dictate what laws to pass, because that is the province of the legislature.

And it is even further from legal for a federal distict court to gang up along with a state administrative branch to force the state legislative branch to pass a law.

That district court is governed by 5th circuit law, and I don't think they will uphold any such ruling by a federal district court.

Here is a case (Texas, Bush v US) where Bush as governor sued on immigration issues, and the 5th Circuit Court of Appeals discussed state rights v federal rights.

That case cites NY v US, where the 10th Amendment, state rights v federal rights, is discussed.

I think the Mississippi AG was correct when he said:

Hood said for him it is a "state's right issue," a question of who should determining Mississippi election law - the state Legislature or a federal judge?

(ibid, your link). Remember that several federal district courts have also held voter id laws unconstitutional when they operate, in effect, as a poll tax.