There's still plenty of difference between e.g. Texas and California. There ought to be some significant level of cohesion between constituent states in a fede

There's still plenty of difference between e.g. Texas and California. There ought to be some significant level of cohesion between constituent states in a federation (like the US or India) or even a confederation (like the EU or Switzerland), else the common market and the common law system won't be able to function. It should not be overdone though.