In this video Sandra Day O'Connor expressed her opinion that both houses in the state legislatures need to be based on the principle of one man one vote. If in her opinion it was unconstitutional for counies to be equally apportioned in the states why would not be unconstitutional for the staes to be equally appoerioned on the U.S. Senate?
In Congress, one house represents the people proportionatley and the other house represents the states equally. This system provides the states with the ability to prevent the abuse of power by the House of Representatives.
The representation of the counties in the states upper house of the state's legislature prevents the complete domination of the people living in the smaller rural counties.