Some more numbers on the Senate's rural bias:

If all Senate seats were up at the same time and we assume D pres states go D down-ballot, Dems would have to win a national landslide of ~19 points to control a supermajority. Reps would just need to win by just 2(!) for 67 seats.

If you order the states by their partisan leans, the 67th seat for Democrats falls somewhere between Mississippi (R+19) and Missouri (also R+19), whereas the 67th seat for Republicans is between Nevada (D+1) and VA (D+2).

The thing about the stupid "We're a republic, not a democracy!" comments is that republics are supposed to have indirect **representation** for voters — and under no reasonable national parameterization can you call what the Senate is doing today "representation."