1968: At the height of the Vietnam War, America is gripped with a crisis of conscience: Millions of citizens, mobilized by a movement started on college campuses, vocally oppose the U.S. actions inSoutheast Asia.

Today: Politicians still fear that popular support for their actions will be split if a military situation is perceived to be "another Vietnam."

1968: Baseball isAmerica's most popular pastime.

Today: Television viewership for football has eclipsed baseball's audience. Furthermore, millions of Americans now play and watch soccer, which is the world's most popular pastime.

1968: A public figure such as a professional ballplayer can lead a fairly normal life, driving from his house to the stadium, past his fans.

Today: Since entertainers such as John Lennon (1980) and Selena (1995) were killed, all public figures are aware of the need for added security.

1968: The average major-league baseball player's salary is $19,000. The minimum salary is...