I can't say with certainty that slavery would have ended more quickly and more completely if the South had been allowed to leave and escaped former slaves had been allowed to remain free, and the North and the rest of the world had been a positive influence on the South. However, it's certainly a possibility that it would have ended sooner if the southern slave owners had agreed to a system of compensated emancipation and freed the slaves without a war and without secession, as most nations that ended slavery did. That absolutely would have been preferable to the Civil War as it happened.

The United States is a rogue state violating international law in many, many ways that California wouldn't have to if it seceded and became a nation.

Climate change is so unimaginable that most Americans deny it's happening.

No other nation killed people the way the United States did to end slavery.

Many militarists would like to see California's votes vanish from the national electoral system, which would then become more Republican.

Slavery remained in the Deep South by other names - in prison programs with charges over nothing and eternal debt that threatened every African-American in the South right up through World War II. And that was after killing three-quarters of a million people, destroying cities, and creating hostility that exists to this day over the the Confederate flag and the racism it symbolizes, all brewing out of bitterness over a war that didn't have to happen.

Imagine Jon Stewart if he gave a damn. He's like Howard Zinn after 12 beers.