Unfortunately, it is not fundamentally unconstitutional. Scotus might or might not shoot down portions.
See Article I Section 4 “times, places, and manner” clause.
It is in there because under the Articles of Confederation, the states often did not send delegates to Congress. The 1787 Framers couldn't be sure the states would hold congressional elections, so the new government reserved the power to make sure the states attended to their duty.