President Barack Obama dismissed Republican critics of a nuclear disarmament treaty he signed with Russia Thursday, brushing off an attack from Sarah Palin.

"Last I checked, Sarah Palin's not much of an expert on nuclear issues," Obama told ABC News.

The conservative darling told Fox News on Wednesday that Obama was naive to make a deal with the Russians.

"No administration in America's history would, I think, ever have considered such a step that we just found out President Obama is supporting today," she told Fox.

"It's kinda like getting out there on a playground, a bunch of kids, getting ready to fight, and one of the kids saying, 'Go ahead, punch me in the face and I'm not going to retaliate. Go ahead and do what you want to with me.'"

Obama, who signed the treaty with Russian President Dmitry Medvedev in Prague, faces a challenge in getting the treaty ratified in the Senate where his fellow Democrats are eight votes short of the 67 votes required.

But he shrugged off the criticism from the right, saying he would rather take advice from his top military advisors than Palin when it comes to nuclear issues.

"If the secretary of defense and the chairman of the Joints Chiefs of Staff are comfortable with it, I'm probably going to take my advice from them and not from Sarah Palin," he said.

Earlier, a CBS News poll said Palin continued to receive unfavorable ratings from the general US public and support from Republicans.

Palin has emerged as a media personality with her own show on Fox News but nearly four in 10 voters who identified themselves as conservatives said they had no opinion of her or knew too little about her to have an opinion.

Twenty-four percent of Americans viewed Palin favorably, compared to 38 percent who hold a negative opinion of her according to the poll conducted March 29 through April 1. Thirty-seven percent of respondents said they were undecided or had not heard enough about her to offer an opinion.

Only seven percent of Democrats said they viewed her favorably and 59 percent viewed her unfavorably.

In contrast, 43 percent of Republicans were positive and 16 percent were negative about Palin, who has become a spokesperson of sorts for the right-wing Tea Party movement.

George Stephanopoulos of ABC News spoke with President Obama while in Prague Thursday, April 8, 2010:

This video is from ABC's Good Morning America, broadcast April 9, 2010.

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