How do Republicans win California now?

[America's Sweetheart ❤/𝕿𝖍𝖊 𝕭𝖔𝖔𝖙𝖞 𝖂𝖆𝖗𝖗𝖎𝖔𝖗]

It would require some sort of realignment, wherein the Republican Party becomes socially moderate, liberal on immigration, and center-right on economics.

[America's Sweetheart ❤/𝕿𝖍𝖊 𝕭𝖔𝖔𝖙𝖞 𝖂𝖆𝖗𝖗𝖎𝖔𝖗]

It would require some sort of realignment, wherein the Republican Party becomes socially moderate, liberal on immigration, and center-right on economics.

That may be enough to win California circa 1996 or even 2004, but the California of today is also quite left-wing economically due to generational replacement and demographic changes.  It will vote for the more progressive of two parties in almost any alignment of the two parties.

At the very least, going left on social issues and immigration should allow Republicans to at least keep California within 10-15 points in a close national election.

[America's Sweetheart ❤/𝕿𝖍𝖊 𝕭𝖔𝖔𝖙𝖞 𝖂𝖆𝖗𝖗𝖎𝖔𝖗]

A peek at the electoral college maps of 2000, 2004, and 2016 indicates that Republicans don't even have to try to win California.

That doesn't really answer the question though. 

[America's Sweetheart ❤/𝕿𝖍𝖊 𝕭𝖔𝖔𝖙𝖞 𝖂𝖆𝖗𝖗𝖎𝖔𝖗]

How much did Schwarzenegger’s tenure as governor hurt the gop there

Not as much as Pete Wilson's did.

[America's Sweetheart ❤/𝕿𝖍𝖊 𝕭𝖔𝖔𝖙𝖞 𝖂𝖆𝖗𝖗𝖎𝖔𝖗]

By becoming a leftist party.

I'm sure your definition of such a term would match up with a very small portion of the American people.

His definition of a leftist is probably anyone to the left of Reagan.

[America's Sweetheart ❤/𝕿𝖍𝖊 𝕭𝖔𝖔𝖙𝖞 𝖂𝖆𝖗𝖗𝖎𝖔𝖗]

Wait for the complete socioeconomic assimilation of Hispanic immigrants á la Italian, Irish, and Polish voters.

I don't think Hispanic citizens are too happy with the GOP's current rhetoric on immigration either.

[America's Sweetheart ❤/𝕿𝖍𝖊 𝕭𝖔𝖔𝖙𝖞 𝖂𝖆𝖗𝖗𝖎𝖔𝖗]

At some point in the 21st century, we will have an extremely unpopular Democratic president who will put all of safe/solid D states in play. Polarization isn’t going to last forever, and I assume we will revert to the mean and get back to having alternating landslides in presidential elections.

Bush's 25% approval rating, extremely unpopular Middle East quagmires, botched Katrina response, and even topping it off with an economic collapse less than 2 months (!) before the election didn't put safe R states into play unless you count Indiana. I don't see it happening.

Obama is a black and a closet Muslim, you see. Those Kerry 2004 counties in the South and in Appalachia didn’t just switch because they suddenly liked Bush’s eight year run and McCain’s promise of another four years of Bushism!

To be fair, these counties mostly swung and trended against Gore and Kerry as well so it could be seen as just the continuation of an existing trend.

[America's Sweetheart ❤/𝕿𝖍𝖊 𝕭𝖔𝖔𝖙𝖞 𝖂𝖆𝖗𝖗𝖎𝖔𝖗]

Libertarian tech billionaire vs. radical SJW Dem in a year with a Dem president in office.

A "radical SJW dem" would have no problem getting elected in California.