Presidential contender Barack Obama won the endorsement of a former rival Tuesday in his battle with Hillary Clinton for the Democratic Party nomination. Obama also got some good news in national polls as he and Clinton prepare for a debate later Tuesday in Cleveland, Ohio.



Obama was endorsed by Senator Chris Dodd of Connecticut. Dodd pulled out of the presidential race shortly after a poor showing in the Iowa caucuses in early January.



"I believe Barack Obama has the experience, the ability, the vision to lead this country and to make a difference for us, both at home and abroad, a significant difference. The hour is getting late and that opportunity is not going to last forever," he said.



Dodd endorsed Obama at a news conference in Cleveland where Obama is campaigning one week before crucial primaries in Ohio and Texas that could be decisive in the battle for the party nomination.



Two new national public opinion polls show Obama has moved into a healthy lead over Clinton. A New York Times/CBS News poll has Obama out in front by a margin of 54 to 38 percent. Another survey by USA Today and the Gallup organization shows Obama leading Clinton 51 to 39 percent.



Obama says he remains focused on the upcoming primaries in Texas and Ohio on March 4. But he is also looking ahead to a possible general election match-up with the presumed Republican candidate, Senator John McCain of Arizona.



"John and I are going to have a big set of disagreements and we are going to have a vigorous debate, because I think that he has tied himself to a set of policies that are not good for America and are policies that I intend to reverse when I am president of the United States," he said.



Clinton is hoping to stop Obama's momentum in Texas and Ohio. Clinton leads in the latest polls in Ohio and is about even with Obama in Texas.



Clinton has been touting her foreign policy experience as an asset in recent campaign rallies and speeches.



"The American people do not have to guess whether I understand the issues or whether I would need a foreign policy instruction manual to guide me through a crisis, or whether I would have to rely on advisers to introduce me to global affairs," she said.



Both campaigns are trading accusations over a photograph circulating on the Internet that shows Obama in traditional African garb during a visit to Kenya in 2006. The Obama camp accused the Clinton campaign of circulating the photo as part of a smear campaign, a charge the Clinton campaign denied.

In the Republican race, McCain continues to lead former Arkansas governor Mike Huckabee in both Texas and Ohio. A McCain sweep of the upcoming primaries on March 4 would move him to within striking distance of securing the 1,191 delegates needed to clinch the Republican nomination.



McCain told reporters during a campaign stop in Ohio that his chances of winning the election in November could hinge on his ability to convince Americans to stay the course in Iraq.

"I believed this new strategy would succeed in Iraq, not because I am the smartest guy in the world, but because I studied and I have had 20 years of experience in every major national security challenge this nation has faced," he said.

In the latest general election match-ups in the USA Today-Gallup poll, Obama defeated McCain by a margin of 49 to 45 percent, while McCain led Clinton by 49 to 47 percent.