Elaine C. Kamarck is a senior fellow at the Brookings Institution and the author of “Primary Politics: Everything You Need to Know About How America Nominates Its Presidential Candidates.”

It was a bloody year. Every night in 1968 Americans watched the Vietnam War rage on television. Casualties from the war had increased dramatically in 1966, again in 1967 and again in 1968. When Americans weren’t tuning into the dismal news from Vietnam, they were watching race riots in major cities. In the nation’s capital, the barbed wire and soldiers at Chevy Chase Circle were just one painful indication of the conflict erupting between black America and white America. The violence spread across college campuses and struck major political figures: Martin Luther King Jr. was assassinated on April 4, 1968; Robert F. Kennedy, brother of the assassinated president, was shot shortly after midnight on June 5, 1968, and died on June 6.

It was in this climate that “America the Violent” (as Time magazine described the nation) held the 1968 election. Aram Goudsouzian, chair of the history department at the University of Memphis, recounts the campaign through the stories of eight major players: President Lyndon B. Johnson, former vice president Richard Nixon, Sen. Eugene McCarthy, New York Gov. Nelson Rockefeller, Sen. Robert Kennedy, California Gov. Ronald Reagan, Vice President Hubert Humphrey and former Alabama governor George Wallace.

The organization of the book provides some fresh insights. Goudsouzian’s narrative takes us into a political world different from today’s — a vanishing world where a candidate’s nomination was influenced but not determined by the primaries.

In the 1968 election cycle, the last of its kind, a strong primary performance did not automatically translate into delegates. The primaries were more like tryouts for professional sports teams, with the scouts being the powerful party leaders who made the ultimate decision on which candidate prevailed as the party’s representative. (In today’s parlance those party leaders are the much-maligned “superdelegates.”) In the chapter on Nixon, Goudsouzian shows that his challenge was to prove himself to the bigwigs on television so that he could erase the memory of his disastrous television debate with John Kennedy in 1960. And he did. Under the tutelage of the late Roger Ailes, later the Fox News impresario, Nixon showed himself to be a competent, if not charismatic, TV performer.

By the time Rockefeller entered the race for the Republican nomination, Nixon had it sewn up. Although Rockefeller spent a ton of money and moved up in the polls, he couldn’t persuade many delegates to vote for him. Reagan posed the other potential challenge to Nixon. “Reagan’s strategy,” Goudsouzian writes, “was to avoid the primaries, win party support, and wait to see if Nixon faltered . . . ‘If he fails, we will want every delegate he has,’ ” said an anonymous confidant. Nixon ultimately captured the nomination.

On the Democratic side, McCarthy, voicing strong opposition to the Vietnam War, shook the political establishment with a surprise second-place finish in New Hampshire. His strong showing and widening protests later prompted Johnson to withdraw from the race.

Kennedy, another strong contender, generated enormous crowds and attention. But, in contrast to today’s system, celebrity was less important than party loyalty. Most veterans of his brother’s 1960 campaign warned Kennedy “that Johnson controlled too many state delegations.” Defying the warnings, Kennedy nonetheless jumped into the race a few weeks before Johnson dropped out. He had no choice but to contest primaries and try to use those victories to shake loose delegates. Like Rockefeller, he spent a lot of money, mostly to no avail. The delegates that had been locked up by Johnson moved over to Humphrey. Whether Kennedy’s primary victories, especially his last one in California, could have shifted establishment delegates to him will never be known. Clearly he had momentum among voters, but he was assassinated right after declaring victory in California.

Humphrey won the Democratic nomination, but his delegates were Johnson’s people. He needed the president’s support to keep the delegates. In those days delegates were semiautonomous actors, and Humphrey risked losing Johnson’s support — and the delegates — if he broke with the president too radically. But at the same time, to win over the new antiwar faction of the party represented by Kennedy and McCarthy, and to heal the divisions in the party, Humphrey needed to signal some distance on Vietnam. But the 1968 system stymied Humphrey’s effort. He had entered the race too late to run in primaries where he could have perhaps carved out his own position on the war.

While the two major parties headed toward their conventions, Wallace, a former governor of Alabama, was running as an independent third-party candidate and relying on overtly racist appeals. His candidacy posed a big threat to the Democratic base, because Wallace was popular in the South and among labor union members.

And herein lies the lasting legacy of the 1968 election. The turmoil of that election, especially on the Democratic side, where the New Deal coalition of Southern, labor and liberal voters seemed to be bursting apart, gave life to a reform movement that ended up replacing the discretion of party leaders to choose delegates. Instead, delegates were bound to primary winners. Very few of the actors at the time appreciated just how far-reaching these changes would be. In a few short years, the power of party leaders was replaced by a flood of primaries.

If the old nominating system was cut off from voters and thus from the forces demanding change, the new nominating system is solely in the hands of voters. In the years since 1968 the new system has produced many nominees who probably would have been selected in the old system as well — think Sen. Robert Dole and Vice President Al Gore. And it has had some big misses: Think George McGovern in 1972. But until 2016, it had never produced a nominee who was a total outsider with no government experience, demagogue-like qualities, and a disdain for the Constitution and the separation of powers. That is the danger of the new system and the legacy of 1968.

Correction: An earlier version of this review incorrectly said that Robert F. Kennedy was shot on June 6, 1968. He was shot shortly after midnight on June 5 and died on June 6. The review has been corrected

Elaine C. Kamarck is a senior fellow at the Brookings Institution and the author of “Primary Politics: Everything You Need to Know About How America Nominates Its Presidential Candidates.”

The Men and the Moment

The Election
of 1968 and
the Rise of Partisan Politics in America

By Aram Goudsouzian

North Carolina. 220 pp. $25