The votes of young Americans, religious conservatives, women, Hispanics and African-Americans could decide the next president of the United States.
More than 50 million Americans are between the ages of 18 and 30, making their support critical to Republican presidential candidate John McCain and Democratic Party nominee Barack Obama. Both campaigns are actively courting this bloc.
A recent poll by the Harvard Institute of Politics indicates Obama is the favored candidate among this young group.
Opinion polls also show Obama with an overwhelming lead among African-Americans. He energized this base by making history this year as the first African-American to become a presidential nominee for a major U.S. political party.
Religious conservatives were a key force that helped push Republican President George Bush to victory in 2000. McCain has worked to mend long-standing rifts with conservatives, and most appear to be rallying behind him now. His vice presidential pick, Sarah Palin, has energized this base.
Both camps also are trying to win over the millions of supporters of Hillary Clinton, including the many women who supported her history-making run for the Democratic nomination. Although Palin, the first female Republican vice presidential nominee, has energized some female voters, a recent poll indicates that Obama leads in this bloc.
The Bloomberg/Los Angeles Times survey says 49 percent of women plan to vote for a ticket led by Obama, while 40 percent choose McCain and Palin.
A recent Quinnipiac University poll shows McCain leading among males and white voters, although Obama is leading overall nationally.
Obama and McCain also are trying to woo Hispanic voters, campaigning in states with large Hispanic communities and airing campaign advertisements in Spanish.
There are at least 10 million eligible Hispanic voters in the United States. Their vote could affect the results in some key "battleground" states like Florida, Colorado and New Mexico. Opinion polls show Hispanics favoring Obama over McCain.