Actually, being a former leftist, I can say that they very well might be happy to let those states go. Remember, those states are a huge impediment to their plans and if they’re not part of the US, the resistance to their agenda will be much reduced.
Imagine if the California contingent in the House didn’t have to contend with the similar-sized Texas contingent telling them “no” every time they want something.
Most of the leftists I know would not want us to secede only because they want to control us and make us work and give them our pay check. Now that they can win elections mostly by fraud and promising welfare they need slaves to pay for it.
As a former ‘rat myself, I think this the really unexplored aspect of this issue: why it might make sense for the other side. In the immediate sense, losing one large red state or a few small ones completely tilts the balance of power in the electoral college. Not to mention how those states act to prevent realization of socialist fantasies.
And then there is the cultural aspect. The deep blue cities view the red areas as being full of illiterate knuckle draggers. Men who want nothing more than to beat their wives and burn crosses. Women who are the embodiment of trash. Inbred children who sit on the porch and play banjos. There is no love lost here.
While I’m personally undecided on the issue, there are some aspects that most people on both sides of the fence would like.