King offered his audience a range of solutions to the problems he outlined above: “a guaranteed minimum income for all people, and for all families of our country”; an immediate end to the war that was “allowing the Great Society to be shot down on the battlefields of Vietnam every day”; eradication of poverty throughout the nation; and real integration, extending beyond public accommodations to the corridors of power...Long story short, our man didn't just declare victory and go home to play some video games after the Civil Rights Act. Up until the day he was shot (he was supporting a sanitation workers' strike in Memphis) he was pushing for a full slate of lefty policies on economics and foreign policy.
The tragic historical counterfactual of my lifetime concerns butterfly ballots and Bush, leading into a disastrous war. It's harder for me to estimate the consequences, both because I'm no expert on the time period and because the counterfactuals get really murky, but I imagine they're even bigger: What would've happened if not for the assassinations of 1968, both of Martin Luther King and Bobby Kennedy?
With an enormously credible progressive leader like King still alive, would the more wayward elements of the American left have been absorbed into a more productive political framework? And with a giant like him still pushing for the whole slate of progressive goals, how much could we have accomplished? If Bobby had survived, won the presidency, and ended the war, how would the last forty years of American history have gone? The possibilities are so far-reaching that it's dizzying to think about.