I wouldn't honestly care if California seceded, as long as we don't give them another dime or fund them in any way.
Without California:
Electoral vote:
Trump: 304
Hillary: 172
Popular vote:
Trump: 58,496,350
Hillary: 57,091,275
U.S. House of Representatives:
Republican: 227
Democratic: 155
U.S. Senate:
Republican: 52
Democratic: 44
Independent: 2
Federal money taken from California: $292,564,000,000 (FY2012)
Federal money given to California: $343,725,000,000 (FY2013)
If the above numbers are correct, it would suggest that no matter how much revenue comes out of California, or how robust their economy is, it still takes in more federal money than it gives, so getting rid of it, wouldn't seem to hurt the U.S. all that much...