At 72, McCain would be the oldest first-term president and only the second to be divorced, following Ronald Reagan, as well as the first to have served in the Vietnam War. Palin, his vice president, would be the first major-party candidate from Alaska.
If Obama, 47, wins, it will be because he unified a broad coalition of minorities, youth, independents and so-called "Obamacans or Baracafella" -- moderate Republicans. His running mate, Joe Biden, would be the first Roman Catholic vice president.
For the first time in a half century, voters may also tip the balance in Congress to the Democrats in what may be the largest gain since the era of Franklin D. Roosevelt.
"We're all fixated on the obvious firsts, like race and gender, but the ending is as important as the beginning," said Smith. "We are looking at the end of 40 years of conservative dominance in American politics, which began with Richard Nixon in 1968 and was strengthened by Ronald Reagan."
Obama has a narrow lead in the opinion polls in traditional red states like Virginia, North Carolina and Florida, which have not voted blue since Dixie-crats moved away from the party after the Civil Rights Act in 1964. That political shift was solidified in 1984 when Ronald Reagan carried the Old South.
An Obama victory could signal the end of that era, one which President Lyndon B. Johnson invoked when he signed the Civil Rights Act of 1964, which outlawed segregation. According to historians, Johnson put down his pen and told an aide, "We have lost the South for a generation."
"That generation is over," civil rights activist Rev. Sharpton told ABCNews.com. "Whites and blacks have fought to change that. But we've seen a progression of black mayors and winners in statewide races. It's an idea whose time has come and will vindicate us if we use it for substantive change."
Still, Obama was also offered Secret Service protection earlier than any other previous candidate, which some say underscores the racism that still exists in America.
The Constitution was amended in 1870 to allow blacks to vote, but it wasn't until the Civil Rights Voting Act of 1965 that they gained full access to the ballot. The first minor party black presidential candidate was the late New York Congresswoman Shirley Chisholm in 1972, followed in 1984 and 1988 by civil rights activist Rev. Jesse Jackson, who sought but failed to obtain the Democratic nomination. Today, the Congress has 42 African Americans and two states have black governors.
Today, African Americans make up 13 percent of the U.S. population, just behind Hispanics at nearly 15 percent.
Sharpton, who ran his own unsuccessful campaign for president in 2004, said Obama's being named to a major ticket is a watershed event.
"If Obama wins, it will be the first time I can honestly look every child in the eye and say, 'you can grow up to be the president of the United States,'" he said. "It fulfills part of Martin Luther King's dream to be judged by the content of our character, not the color of our skin."
But 2008 is a watershed for more than African American politics.
Women, who gained the right to vote even later than blacks, in 1920, shattered "18 million cracks" in the glass ceiling with the hard-fought candidacy of New York Sen. Hillary Clinton. Her campaign came on the heels of Nancy Pelosi becoming the first female speaker of the U.S. House of Representatives in 2007.