(Xinhua)
Updated: 2008-04-23 08:46

WASHINGTON -- US Senator Barack Obama of Illinois has widened his lead nationally for the Democratic presidential nomination despite a furor over his comments about small-town Americans, a USA TODAY/Gallup Poll out Tuesday finds.

US Democratic presidential candidate Sen. Barack Obama (D-IL) talks to a child during a campaign stop in Philadelphia, Pennsylvania April 22, 2008. [Agencies]

The poll also show his rival Senator Hillary Clinton of New York is getting more of the blame among those who say their contest has become too negative.

As the candidates make a final push for votes in Tuesday's Pennsylvania primary, Obama leads the survey by 50 percent to 40 percent among Democrats and voters who lean Democratic nationwide.

That's a bigger edge than the 7 percentage point lead he held in the USA TODAY poll last month.

Seven of 10 respondents say Obama "respects working-class Americans" rather than looks down on them -- a slightly more positive reading than that for Clinton or John McCain of Arizona, the Republican candidate.

Meanwhile, US President George W. Bush set an unwelcome record, scoring the highest disapproval rating of 69 percent in the history of the Gallup Poll, which dates to Franklin Roosevelt' s tenure.

Bush's approval rating is 28 percent, matching the low point of his presidency.

Harry Truman still holds the record for the lowest approval rating, at 23 percent.

A record number of Americans, 63 percent, now say the invasion of Iraq was a mistake.

In the survey, Obama edges McCain 47 percent to 44 percent among registered voters. while Clinton beats McCain 50 percent to 44 percent.

Democrats are split on whether the continuing primary campaign is damaging the party's prospects in November.

Half say it is hurting the party and leaders should get together and back one of the contenders while half say it isn't hurting the party and should continue until a candidate clinches the nomination.

Democrats are divided, too, about whether the contest has become too negative. Among the half who say it has, 43 percent blame Clinton, 3 percent blame Obama. 53 percent blame both equally.

The telephone survey of 1,016 adults, taken April 18-20, has a margin of error of +/- 3 points for the full sample.