The Guarantee Clause of the Constitution
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.
For this qualification to be met the senators chosen to represent the states in the Senate must be chosen in an indirect election. If the senators are chosen directly by the people it is an example of a democratic rather than a republican form of government.
The direct election of senators violates the guarantee clause in the Constitution.
Replies
So does allowing illegals to vote, which turns the state into a democracy.
So does allowing the states to give the electoral votes over to whomever won the popular vote.
I wrote PTrump about this, and actually received by email, a letter in response, thanking me, instead of just the "Thank You" generic form.
I also wrote that no votes should be counted in federal elections from states where the A.G. allows illegals to vote or where the governor or any mayors welcome illegal aliens. Again, it turns the states into democracies. Plus what the direct election of senators does, as you wrote.