WASHINGTON – Americans’ preferences about the two presidential candidates are sharply divided by race, a Washington Post-ABC News poll found, as Sen. Barack Obama enters the 2008 campaign as the first African-American on a major party’s presidential ticket.

Obama enjoys an overwhelming 90 percent of support from African-American adults, the poll found, while Republican Sen. John McCain garners just 7 percent. McCain, meanwhile, gets 51 percent support from white adults while Obama takes 39 percent.

Among all adults, the poll found, Obama enjoys a lead of six percentage points over McCain, 48 percent to 42 percent.

Among those considered most likely to vote, however, the presidential race is a draw: McCain scores 48 percent to Obama’s 47 percent.

While 39 percent of white adults support Obama, a majority of whites also view the Illinois Democrat as a “risky” choice for president. Among whites, 52 percent said Obama is a risky pick, compared to 47 percent of whites who said he is “safe.” Among blacks, 78 percent found Obama safe versus 21 percent who said he is risky.

Whites made up 77 percent of all voters in 2004 while blacks represented 11 percent, the Post reported, citing network exit polls.

Both black and white adults believe Obama’s candidacy will help race relations in the U.S. more than it will hurt them. However, African-Americans are far more optimistic, with 60 percent responding that Obama’s candidacy will help race relations. Only 8 percent said it would hurt and 31 percent said it wouldn’t make a difference.

Among white adults, 38 percent said Obama’s candidacy would help, while 17 percent said it would hurt race relations, and 43 percent said it wouldn’t make a difference.

In the same poll, almost half of all Americans say race relations in the U.S. are in bad shape and three in 10 admit feelings of racial prejudice.

The poll was taken June 12-15 among a random sample of 1,125 adults, including additional interviews with African-Americans, for a total of 201 black respondents. The full survey’s results have a margin of error of plus or minus three points.

Obama was taking a break from campaigning on Sunday, spending the day in Chicago.