It isn't clear whether Senator Kennedy would have gone on to to win the Democratic nomination for President of the United States. It seems conceivable. He won the California primary by 5%, but prior to that he had lost the Oregon primary and indicated he would likely drop out of the race if he lost in California.
It is clear that the Democratic Party lost momentum after the assassination. The country was in turmoil. Political radicalism was rampant. Protests against the war in Vietnam were becoming increasingly more virulent and violent.
I do not know how the world would have been different. Indeed, I cannot know if the world would have been a better place or a worse one if Senator Kennedy had survived and gone on to win the general election in November.
I believe it would have been better. I believe Robert Kennedy had the ability to unite a country torn by vehement attitudes about Vietnam, civil rights, and a cultural divide between the Greatest Generation that won World War II and an anti-establishment generation of Baby Boomers looking to make their own way.
But I was only 4 years old in 1968. My belief that things would have been better is washed through the eddies of the 43 years I've lived in and learned about the world since that horrible day.
In his eulogy for his brother, Edward Kennedy said,
My brother need not be idealized, or enlarged in death beyond what he was in life; to be remembered simply as a good and decent man, who saw wrong and tried to right it, saw suffering and tried to heal it, saw war and tried to stop it. Those of us who loved him and who take him to his rest today, pray that what he was to us and what he wished for others will some day come to pass for all the world.
As he said many times, in many parts of this nation, to those he touched and who sought to touch him: "Some men see things as they are and say why. I dream things that never were and say why not".
We can all make a difference in the world. We have the power to choose a smile over a frown, to hold a door open, to give back some of what we take.
Few will have the greatness to bend history itself; but each of us can work to change a small portion of events, and in the total of all those acts will be written the history of this generation. (Robert Kennedy)
Robert Francis Kennedy
(20 November 1925 - 6 June 1968)