In 1993, the California Republican Assembly (a conservative activist group chartered by the state party) passed a resolution declaring illegal immigration to be an economic positive for the state of California. A year later the party decided to go all-in on anti-immigration hysteria and paid for some disturbingly racist ads ("they keep coming"). This gave them short-term gains politically but by the 2010s the Republican party fell into permanent minority status with little prospect for even reaching the level to keep the democrats out of supermajority status in the near-term future.
Ralph Abernathy and Walter Mondale supported Ceasar Chavez's marches to fight against illegal immigration. Ronald Reagan had no problems with using such strikebreakers