In 1966, Republicans found ways to invoke the fears of white voters around the Civil Rights act and other reforms, using a sanitized lexicon.
In 1966, scores of Democrats lost their House and Senate seats, as cagey conservative politicians like Richard Nixon (the GOP’s campaigner-in-chief that year) and Ronald Reagan (who defeated incumbent California Governor Pat Brown) developed a sanitized lexicon to appeal to white voters’ anxieties about civil unrest, the economic and political advances of black Americans, and the expansion of the federal welfare state. It would prove a winning formula for over 20 years. In effect, the political right took a drubbing in one cycle, but it learned from its loss and began building a powerful rhetorical case against the Great Society. (Source)
1966 was also NASA’s zenith. Did Great Society backlash doom it? See NASA’s 1966 Zenith