When Morton retired, he surprised many, who considered him at the peak of his political power. However, he opposed the Vietnam War despite being criticized by Rep. William Cowger from Kentucky. Also, he was both depressed by the urban violence after the April 1968 assassination of Martin Luther King Jr. and that of Robert F. Kennedy a few weeks later, and disappointed in his party's failure to address the broader social issues. He also ultimately counseled then-President Lyndon Johnson to decline to seek re-election, and he supported the unsuccessful presidential candidacy of Gov. Nelson Rockefeller of New York.