Nixon was trailing the Democrats in the polls as late as 1971. I think RFK would run out of a sense of conviction to stop the war and heal social divisions being widened by Nixon. He'd lose to Nixon in a close race similar to 2004. Close enough that after Watergate RFK is given a second chance in 1976.
Honestly, I think RFK could have pulled it off in 1972.
Let's say that he doesn't run in 1968. That's easy. Just have Kennedy's preferred candidate George McGovern run instead of Gene McCarthy in the primaries (which is something he very nearly did).
George McGovern, running as the sole standard bearer for the anti-war movement, would perform very well in the primaries, collecting all of the votes that went to Bobby and Gene IOTL. After being almost defeated by a
South Dakotan of all people, President Johnson still leaves the race, and with that Humphrey joins in. As McGovern gathers delegates through primaries, and Humphrey behind closed doors, the race going into the Convention becomes quite close. However, Humphrey still wins. This disappoints Robert Kennedy, who is at the Convention to support McGovern. This also disappoints the protesters outside, who riot.
The 1968 DNC is still remembered for all of it's chaos, so when Humphrey runs against Nixon he still loses.
Kennedy, seeing the continued decay of the cities and the endless violence wrought by Vietnam, begins to regret not running in 1968, which furthers his resolve for 1972. As he wins re-election to the Senate in 1970, Kennedy becomes the most outspoken opponent of the Nixon administration, whom he charges with continuing to divide America. It becomes very apparent to both voters and party bosses that Bobby will be the front-runner in 1972.
As 1971 draws to a close, Bobby doesn't hesitate a second time. He declares himself a Presidential candidate. With the newly-expanded primary season rapidly approaching, the three biggest contenders for the nomination are Robert Kennedy, Ed Muskie, and George Wallace. Robert Kennedy performs fairly well against the two in the first primaries, but then his entire crusade nearly comes to an end in Wisconsin. After a debate between Kennedy and Wallace, the ill Arthur Bremer shoots Kennedy from across a crowd. Kennedy is very nearly killed, but he survives with little long-term injury. The assassination attempt propels Kennedy to near saintdom, a la Reagan 1981 IOTL, and he easily sweeps the rest of the primaries to win the nomination in sweltering Miami. With most of the Democratic Party behind him now, Kennedy sets his sights at Nixon, determined to dethrone the tyrant who so selfishly let America burn in order to preserve his power.
Despite being fairly popular, especially because of his trip to China, Nixon is still very, very, VERY paranoid at the point. Seeing the charging Kennedy as heralding the end of his Presidency, as well as coming under some suspicion because of his corrupt VP Agnew, Nixon tries to use every trick in the book to smear Bobby Kennedy. He could expose JFK's affairs, or Bobby Kennedy's involvement in wiretapping, or reveal some other damaging material, or even try to spread those unfounded rumors that Bobby and Marilyn Monroe had an affair. He would try to paint Kennedy as the friend of the hippies, but he would have a much harder time doing this because of Kennedy's law and order rhetoric. He also would probably have CREEP still participate in their illegal activities, perhaps even at a more frantic pace. This could mean that they could slip up and make a mistake as they had in Watergate much earlier, perhaps proving to America that their President is a crook much earlier, just like in my favorite TL
McGoverning.
Whatever happens, Kennedy would be a much, much stronger candidate to oppose Nixon than McGovern was, running with a less divided party and a better organized campaign. Not only that but without Bremer shooting him, Wallace runs a third party campaign just as he did in 1968, choosing Lester Maddox as his running mate. So, as Americans enter the polls, no one knows who will triumph.
The results begin coming in. The northeast and Industrial midwest vote for Kennedy. The Deep South sticks with their man Wallace. Nixon and Kennedy both are tied in the electoral count, with the decider of the election being the nation's most populous state: California. Whoever wins there wins the Presidency.
Everyone holds their breath as the Californian votes are counted, until finally a winner is announced. ROBERT KENNEDY WINS CALIFORNIA. And with that, the prince had successfully knocked the tyrant off of his pedestal.
Ok I know this may not be the most realistic scenario (I know more about '68 than '72), but I feel like it could have gone like this if Kennedy lived to 1972. Kennedy would most likely face many economic troubles, but he would be remembered for finally getting us out of Vietnam and for healing America's divisions. He would face Ronnie in '76, and would probably win. This leaves us with Bush Sr. winning in '80, and the rest is history. What do you guys think? It's not anything for a TL (that will be something a little different), just a fun little scenario I thought up. How would an RFK presidency fare from 1973-1981? What could he accomplish? How would he be remembered? What could Nixon have dug up to smear RFK? Could he have even won in the first place, even if Nixon's nefarious activities are exposed earlier?