Democratic presidential candidate, Sen. Barack Obama, D-Ill., pauses for a moment while addressing supporters Friday at a rally in Roanoke, Va. The issue of race in the 2008 election is increasingly popping up with the likelihood of Obama becoming the next U.S. president.

Washington ? Race, an inescapable but explosive issue on which both presidential candidates have trod carefully if not tried to ignore, is increasingly popping up as it’s becoming more likely the country will elect its first black president.

Supporters of John McCain and Barack Obama, though not the candidates themselves, are amplifying the issue in the homestretch.

Among Democratic backers: Rep. John Lewis, the black Georgia Democrat and prominent civil rights leader who accused the GOP ticket of “sowing the seeds of hatred and division” and recalled the atmosphere segregationist Alabama Gov. George Wallace fostered in the 1960s; and Democratic Rep. John Murtha of Pennsylvania, who referred to the western part of his state as “a racist area.”

Among GOP allies: a California group, which distributed anti-Obama literature with stereotypical black America images of a watermelon, ribs and a bucket of fried chicken. Another group put Obama’s incendiary black former pastor, the Rev. Jeremiah Wright, in a TV ad. A Virginia GOP official said Obama would hire rapper Ludacris to paint the White House black.

Among voters who haven’t yet settled on a candidate: “Joe the Plumber.” The Ohioan whose last name is Wurzelbacher and was repeatedly mentioned during the final presidential debate told one interviewer that he didn’t get direct answers to his questions when he met Obama. He said all he got was “a tap dance. Almost as good as Sammy Davis Jr.”

All that, and in the last week alone.

Polls show Obama, the son of a white mother from Kansas and a black father from Kenya, leading nationally and in key battlegrounds little more than two weeks before the Nov. 4 election. He’s already made history as the first black nominee of a major political party, and his candidacy has energized minority voters in ways never before seen.

Among the unknowns: Should Obama win the White House, will racism become a subtext throughout his tenure? Or does his presidency work to soothe emotions still raw four decades after the civil rights movement and nearly 150 years since the end of slavery?

Race has always been in the background of the general election. Obama’s campaign bristles at any suggestion of exploiting Obama’s skin color; McCain’s advisers deeply fear being called racists.

The issue boiled up over the summer.

Obama said Republicans would try to scare voters by saying “he doesn’t look like all those other presidents on the dollar bills.” McCain’s campaign, quick to counter any notion of racism, accused Obama of playing the race card.

A recent AP-Yahoo News poll found that 40 percent of all white Americans hold at least a partly negative view toward blacks. The survey indicated that racial misgivings could cost Obama the White House if the election is close.

In chastising McCain and running mate Sarah Palin, Lewis said, “There is no need for this hostility in our political discourse.” He noted that Wallace also ran for president and “created the climate and the conditions that encouraged vicious attacks against innocent Americans who were simply trying to exercise their constitutional rights.”

Later, Lewis said it was not his “intention or desire” to directly compare McCain or Palin to Wallace.

Obama’s campaign said the Illinois senator didn’t agree with the comparison. But McCain challenged Obama personally at the debate to repudiate the remarks that he called “very unfair and totally inappropriate.”

Obama said Lewis’ comments were not prompted by his campaign and that “he inappropriately drew a comparison between what was happening there and what had happened during the civil rights movement.”