On the morning of March 16, 1968, CBS pre-empted its regularly scheduled television programming for breaking news. Then-New York Sen. Robert Francis Kennedy was prepared to announce his candidacy for the presidency.

As the audience waited for the senator to arrive in the Senate Caucus Room on Capitol Hill, venerable newsman Roger Mudd, who anchored CBS’ coverage for the occasion, set the scene of Kennedy’s decision with these ominous words:

“The senator is doing so in the face of almost solid opposition from the Democratic Party professionals. Only three state [Democratic] chairmen — New York, Oregon and Tennessee — have come out in favor of Mr. Kennedy’s candidacy.”

From that point on, RFK’s presidential campaign to re-create the glamour of Kennedy Camelot at the White House lasted only 80 days.

Kennedy later lost the Oregon primary in an upset to Minnesota Sen. Eugene McCarthy, the antiwar, Bernie Sanders-like candidate of his time. Then, after Kennedy barely won the make-or-break California primary on Tuesday, June 4, he was shot mere minutes after his victory speech at the Ambassador Hotel in Los Angeles. He died at Good Samaritan Hospital on June 6, at 1:44 a.m. Pacific time. He would have turned 43 on Nov. 20, 1968.

RFK was murdered five years after his older brother, President John F. Kennedy, was assassinated on Nov. 22, 1963, in Dallas. The Rev. Martin Luther King Jr. had been assassinated two months earlier than RFK, almost to the day.

At the time of RFK’s death, his chief competition was the entrenched Vice President Hubert Humphrey. He led the Democratic race with 561 delegates, Kennedy had 393 and McCarthy 258. (The incumbent, the pro-Vietnam War Lyndon Johnson, ultimately decided not to seek re-election because of the antiwar sentiment sweeping the nation, which fomented into ugly riots at the Democratic National Convention in Chicago during August 1968 and splintered the party itself.)

Now we ask: “What if?”

Suppose the unspeakable tragedy never happened. What if RFK had been allowed to finish his campaign?

Peter Edelman, now 80, is the Carmack Waterhouse professor of law and public policy at the Georgetown University Law Center in Washington. He was a legislative assistant to Kennedy from 1964 until the assassination.

Asked what would have happened if Kennedy had been able to continue his candidacy, Edelman said: “I do believe RFK would have defeated Richard Nixon for the presidency.”

But.

“The harder question is whether he would have won the [Democratic] nomination,” Edelman insisted.

Kennedy — a rock star to many — attracted the disenfranchised and a Barack Obama-like amalgam of poor Americans, black folk, Catholics, working-class types, Hispanics, farmworkers and the New-Age, long-haired, hippie-style 21-year-olds.

But Humphrey retained the old-guard Democratic power base — the major labor unions and influential political bosses on the state level, such as big-city mayors, members of Congress and governors. It was a time, unlike today, when only 14 states incorporated Democratic primaries, thus backroom deals for delegates and brokered conventions were the norm.

Suppose Kennedy had garnered the Democratic nod. Could he have defeated a formidable foe in the experienced Nixon in the general election?

Nixon had been vice president during Dwight Eisenhower’s two-term presidential administration. And Nixon had galvanized many white voters following the violent unrest by young black citizens seeking retaliation in urban areas nationwide after the killing of King. That’s why Nixon’s core campaign message focused on what he termed the “Silent Majority” (white Americans tired of the growing pains of the civil-rights movement and who fled riot-torn cities), law and order, and securing “peace with honor” in Vietnam.

RFK was the beneficiary of the Kennedy mystique, charisma and wealth, but was that a real, winning advantage for him? Some think not.

Jeffrey A. Engel, director of the Center for Presidential History at Southern Methodist University in Dallas, said: “I would not have put money on him getting the nomination or money on him winning the election; the dynamics were stacked against him.”

That stack was piled with some ardent RFK detractors in the home party: Democrats who negatively viewed him as his brother’s “bouncer” or “strongman” while he was the U.S. attorney general during JFK’s administration. In addition to pursuing Mafia members and corrupt organizations, RFK’s office even brought litigation against some Democratic political machine leaders in black voting rights cases in the deeply segregated South.

Nixon ultimately won the presidency, but what about the specter of a Humphrey-Kennedy ticket?

Arthur I. Cyr, the A.W. and Mary Margaret Clausen distinguished professor of political economy and world business at Carthage College in Kenosha, Wis., said: “Humphrey and Kennedy had heavily overlapping but not identical constituencies. Their styles were also complementary, and they both were careful to maintain good relations. Finally, Nixon was spooked by the name ‘Kennedy.’ ”

Bottom line: The duo could have fielded a winning ticket in November.

Remember, JFK defeated Nixon in 1960 in one of the most electrifying presidential elections in U.S. history.

RFK had his share of missteps, such as supporting Sen. Joe McCarthy’s raging crusade to root out supposed “communists” in government and Hollywood in the 1950s and his authorization to wiretap King’s telephone lines after the seminal March on Washington in 1963. RFK embodied the role of a ruthless grinder in the early 1960s, but appeared to change his brand in the late 1960s — to something of an Andrew Carnegie type, a wealthy luminary who deep inside had a soft spot for common folk.

Some astute political observers mused that JFK was soft on the outside but hard on the inside, while RFK was hard on the outside but soft on the inside. (Recall that poignant April 1967 video of RFK asking impoverished black children during a listening tour of the Mississippi Delta if they had lunch for the day.)

Note what the idealistic RFK said when he announced his candidacy that morning in March 1968: “I do not run for the presidency merely to oppose any man but to propose new policies. I run to seek new policies — policies to end the bloodshed in Vietnam and in our cities, policies to close the gaps that now exist between black and white, between rich and poor, between young and old, in this country and around the rest of the world.”

Even if RFK had lost in 1968, a 1972 campaign surely would have been an option — because he cared.

Said former aide Edelman: “He was wonderful to work with, cared for people on the edges of society for various reasons, would go anywhere to meet people on the peripheries, listened to them, respected them, went to places that a senator had never been, including the senators from their own states. Deeply committed to make a difference, to change this nation for the better.”

Many regular Americans displayed their caring and admiration for RFK in return. His casket was transported by a funeral train for the 226-mile journey from New York to Washington for burial on Saturday, June 8, 1968, at Arlington National Cemetery, near JFK. Hundreds of thousands, perhaps even a million, mourners — black, white, Hispanic, old and young, with all hoping for better times — lined the tracks. Some saluted the train; others waved Old Glory; many openly wept.

After an 80-day presidential campaign cut short by an assassin 50 years ago.