Just because right-wing politicians used "law and order" as a code for race did not mean that concern about crime was illegitimate.

E.J. Dionne, Jr. writes in The Washington Post:

Forty years ago, American liberalism suffered a blow from which it has still not recovered. On April 4, 1968, a relatively brief but extraordinary moment of progressive reform ended, and a long period of conservative ascendancy began.

The assassination of Martin Luther King Jr. and the ensuing riots that engulfed the nation's capital and big cities across the country signaled the collapse of liberal hopes in a smoky haze of self-doubt and despair. Conservatives, on the run for much of the decade, found a broad new audience for their warnings against the disorders and disruptions bred by reform.

A shrewd politician named Richard Nixon sensed the direction of the political winds. When President Johnson's commission on urban unrest released its report in early 1968 and blamed the previous year's rioting on "white racism," Nixon would have none of it. The commission, he said, "blames everybody for the riots except the perpetrators of the riots." He urged "retaliation."

Nixon knew that his call for law and order was drawing working-class whites away from their alliance with the New Deal and the Great Society.

It is easy to forget that the core themes of contemporary conservatism were born in response to the events of 1968. The attacks on "big government," the defense of states' rights, and the scorn for "liberal judicial activism," "liberal do-gooders," "liberal elitists," "liberal guilt" and "liberal permissiveness" were rooted in the reaction that gathered force as liberal optimism receded.

From the death of John F. Kennedy in November 1963 until the congressional elections of November 1966, liberals were triumphant, and what they did changed the world. Civil rights and voting rights, Medicare and Medicaid, clean air and clean water legislation, Head Start, the Job Corps and federal aid to schools had their roots in the liberal wave that began to ebb when Lyndon Johnson's Democrats suffered broad losses in the 1966 voting. The decline that 1966 signaled was sealed after April 4, 1968.

Liberals themselves share blame for the waning of their movement. Just because right-wing politicians used "law and order" as a code for race did not mean that concern about crime was illegitimate. On the contrary, the country was in the opening stages of a serious crime wave and had good reason to worry about rising violence.

Liberalism itself was cracking up in 1968. Liberals had turned on each other over Johnson's Vietnam policy. The old civil rights coalition splintered as advocates of racial integration warred with defenders of Black Power, a slogan voiced in 1966 by a young activist named Stokely Carmichael.