I have advocated for the exact opposite of what you are suggesting. It would involve much less bloodshed. The most populace areas of red states should be allowed to form their own states. The people could choose to stay in the cities or leave to join their former states with fully paid moving and living expenses paid for a pre-agreed upon length of time. There would likely be considerable cross-movement, so it might take some time for the jobs situation to reach equilibrium.

The existing states would lose considerable representation while the "new" states would each gain house representation and two Senate seats. It would effectively flip the US government overnight and force the GOP into a perpetual minority for at least a generation.

Many of the larger cities in red states have greater populations than the rest of the state combined. Some would be larger than entire existing western states, but wouldn't have to deal with the gerrymandering and voter suppression that made them politically subservient.