Democrats used the Sunday morning talks shows to spar over their party’s tight presidential nominating contest, raising fears among some that the increasingly hostile tone of the campaign could haunt Democrats in November.

With polls in Ohio and Texas showing a dead-heat between Sens. Barack Obama (D-Ill.) and Hillary Rodham Clinton (D-N.Y.), Obama supporters said Clinton should make a realistic assessment of her chances should she lose one of the two states on Tuesday.

Obama has won the last 11 Democratic contests and leads Clinton in the overall delegate count.

On the same show, Sen. Dianne Feinstein (D-Calif.), a Clinton supporter, said the junior New York Democrat should continue her quest for the nomination regardless of the outcome of Tuesday’s primaries.

“There's been a lot of talk – well, if Senator Clinton loses this state, she should kind of pack it in. I disagree with that. I think she should stay in the race,” Feinstein said. “This is not an also-ran candidate. Hillary Clinton is a major candidate. She has every right to stay in the race if she chooses to do so.”

Durbin, Feinstein and other Democrats on the Sunday talk shows also debated the merits of a controversial ad the Clinton campaign released Friday. Clinton surrogates also used the programs to attack Obama for not using his subcommittee chairmanship to hold a hearing on Afghanistan, while Obama's campaign criticized Clinton for her vote authorizing the war in Iraq.

If the race continues to drag on past Tuesday, New Mexico Gov. Bill Richardson, a former Democratic presidential candidate, said it could create insurmountable rifts within the party.

“Republicans are united right now. They don't have a divisive primary. It looks like the tone of our campaign is heading much too negative,” Richardson said on the CBS show “Face the Nation.”

“And I want to see us after Tuesday basically come together and see where we are and move on to the general election,” said Richardson, who has not endorsed a candidate and described himself as “torn” about which candidate to support.

Clinton's new ad, debated thoroughly on the shows, depicts a mother looking at her sleeping child, with the narrator saying: “It’s 3 a.m., and your children are safe and asleep. But there’s a phone in the White House, and it’s ringing. Something’s happening in the world. Your vote will decide who answers that call.”

Obama responded with a similar ad saying that the next president who answers the call should exercise judgment, like the Illinois Democrat demonstrated in 2002 when he opposed the authorization for the Iraq war, which Clinton supported.

Obama supporters continued that theme on Sunday.

“The basic question is not whether the president can wipe the sleep out of his or her eyes and think clearly, but the judgment that they’ll use once that phone call is understood,” said Durbin, who voted against authorizing the Iraq war.

Feinstein, who voted to authorize war, said she doesn’t believe the Iraq war can be equated to a critical phone call at the dead of night the president has to field.

“Iraq was essentially a considered judgment that was made, rightly or wrongly,” Feinstein said. “It wasn't a missile on the way to the shores of the United States at 3:00 in the morning.”

The fight over the ad continued between top Obama strategist David Axelrod and Howard Wolfson, Clinton communications director, on ABC’s “This Week.”

“We talk about the red phone -- on the most important question that Senator Clinton has had to deal with in foreign policy, the red phone moment for her, the vote on the war in Iraq, she gave the wrong answer,” Axelrod said.

Wolfson said that a voter should evaluate the “lifetime of experience and judgment” a candidate brings to the job in determining who is best fit to answer such a phone call. But he acknowledged there was no single moment that he could point to demonstrating Clinton’s ability to handle a crisis.

“Well, look, I don't think anybody going into that office can say, if you're not the president, oh, ‘I've gotten a call at 3:00 a.m. and something terrible has happened in Russia,’” Wolfson said.

Wolfson and Axelrod engaged in perhaps the most heated exchange of the day, with Wolfson pressing the Obama campaign to release all correspondence pertaining to a real estate deal between the senator and Tony Rezko, a Chicago businessman who goes on trial this week for corruption charges.

“They should put out all of the information regarding that real estate transaction – all of the e-mails, all of the correspondence, all of the letters, every single piece of information -- so that the public can really look at this and say, ‘What's going on here?’” Wolfson said.

Axelrod stressed that the real estate deal and other interactions the senator had with Rezko had been thoroughly vetted and that there is no evidence of any wrongdoing by Obama. He also pushed back by calling on Clinton to release her tax returns and documents about her time as first lady.

Wolfson said she would release “all of the tax returns that are not currently in the public record” around April 15, and said the documents about her time in the White House would be released soon.

The sniping continued among Democratic senators as well.

On “Face the Nation,” Sen. Evan Bayh (D-Ind.), a Clinton backer, criticized Obama for not holding a hearing on Afghanistan since he became chairman of the European Affairs Subcommittee on the Foreign Relations panel in 2007.

“And as far as I know, [Obama] hasn't chaired a hearing or really focused on this or used his judgment or that place to really do anything about Afghanistan,” Bayh said.

The Hill reported Saturday that Obama has never visited Afghanistan, and has missed two of three Foreign Relations panel hearings on that country since joining the committee.

Sen. Chris Dodd (D-Conn.), who lent his support to Obama last week and dropped his quest for the White House in January, told “Face the Nation” that running for president means that a senator will have to miss votes and hearings on a regular basis.

He added: “It doesn’t serve our interests here to be demeaning the other candidate, in my view. And I’m worried about these ads in a sense creating that kind of environment.”