( Reuters ) - Democratic presidential candidate Hillary Clinton questioned rival Barack Obama's experience in handling a national security crisis on Friday as polls showed her losing ground to Obama before Tuesday's contests in Texas and Ohio.
The Clinton campaign released a new television ad to be aired in Texas, which along with Ohio are crucial to her chances of reversing a string of losses to Obama. It shows children sleeping peacefully in bed as a narrator says:
"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."
The Clinton campaign hoped the new ad would convince voters she would be ready to act swiftly and decisively in case of another September 11-type crisis in the United States.
Obama hit back with an ad of his own, which also showed sleeping children and spoke of a White House phone ringing.
"When that call gets answered, shouldn't the president be the one - the only one - who had judgment and courage to oppose the Iraq war from the start?" the narrator says.
Clinton, a New York senator and former first lady once considered the favorite to win her party's presidential nomination, needs to win Texas and Ohio by wide margins on Tuesday or face the end of her candidacy.
Her struggling campaign got an important morale boost with the news she had raised $35 million in campaign contributions in February, which was the most she had collected in one month. Obama aides declined to say when he would release his fund-raising total but maintained he had continued to out-raise his rival in February. The figures must be released by March 20.
Obama and Clinton held competing rallies in the San Antonio area on Friday evening.
Obama, in reference to Clinton's ad, told his crowd of some 8,000 that Clinton had failed her "phone moment" with her 2002 Senate vote to authorize use of force in Iraq.
"We've seen these ads before. They're usually the kind that play on people's fears and try to scare up folks. But it won't work," he said.
Adding to his momentum, Obama said he had received backing from Sen. John Rockefeller, a West Virginia Democrat who heads the Senate intelligence committee. "Barack Obama is the most qualified person - Democrat or Republican - to lead our country in the face of enormous challenges," he said.
Clinton has repeatedly tried to question Obama's experience but the first-term Illinois senator, who would be the first black president, has ridden a wave of support with a call for sweeping change in Washington.
At an appearance in Waco, Texas, on Friday, Clinton said Obama was "missing in action" in the Senate on key national security issues, including a vote on labeling an Iranian military group a terrorist organization, and failing to hold hearings as head of a Senate subcommittee on foreign policy.
A Reuters/C-SPAN/Houston Chronicle poll released on Friday said Obama holds a slight lead in Texas, 48 percent to 42 percent, over Clinton, who would be the first woman president.
He trails Clinton 44 percent to 42 percent in Ohio - well within the poll's margin of error of 3.8 percentage points. He had been losing to her in Ohio by double digits.
In the Republican race, front-runner John McCain holds commanding leads over his last major rival, former Arkansas Gov. Mike Huckabee. McCain, an Arizona senator, has built an unassailable advantage in delegates who will pick the nominee at the Republican Party convention in September.
But McCain spent Friday tried to distance himself from evangelical leader John Hagee, whose endorsement he embraced on Wednesday despite the pastor's controversial views about the Catholic Church.
"In no way did I intend for his endorsement to suggest that I in turn agree with all of Pastor Hagee's views, which I obviously do not," McCain said in a statement. Hagee wrote a book that claimed Adolph Hitler and the Catholic Church joined in a conspiracy to destroy Jews.
Conservative Sen. Sam Brownback issued a statement supporting McCain.
The poll, conducted by Zogby International, found McCain with big double-digit margins over Huckabee in Texas and Ohio.