Is it a realistic or desirable goal to be nostalgic for the 1950s as one of the best times in American history as a time and values they want the country to return to, and why?
This is a question of historical memory, and like most such questions, it depends on perspective. There is no doubt that the 1950s have been mythologized and idealized, as demonstrated by TV shows like "Happy Days" and the rash of '50s themed restaurants that emerged in the 1980s. Nostalgia for the '50s, however, might not be shared by an African-American person, who experienced the decade in a segregated South. The decade witnessed some of the tensest moments of the Cold War, a bloody conflict on the Korean peninsula, anti-communist hysteria, and, contrary to popular memory, a massive expansion in the size of the federal government.
This is not to suggest that the 1950s were worse than any other decade. The decade also witnessed the birth of rock n' roll as well as many other aspects of American culture that most would agree were positive developments. The point is that historical memory tends to be selective, and many of the people, especially baby boomers, who valorize the decade now viewed it quite differently from the perspective of the 1960s. In any case, defining history by decades is an arbitrary construct to begin with, and whatever "values" we associate with the 1950s were products of the specific social, economic, and political circumstances of the times. Ultimately, nostalgia for the 50s says as much about how people view our own time as it does about that decade.