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This morning on "This Week," ABC News' George Will called Donald Trump a "bloviating ignoramus," questioning why presumptive Republican presidential nominee Mitt Romney is associating with the real estate mogul, who once again falsely questioned President Obama's birthplace this week.

"I do not understand the cost benefit here," Will said on the "This Week" roundtable. "The costs are clear. The benefit - what voter is gonna vote for him (Romney) because he is seen with Donald Trump? The cost of appearing with this bloviating ignoramus is obvious it seems to me.

"Donald Trump is redundant evidence that if your net worth is high enough, your IQ can be very low and you can still intrude into American politics," Will added. "Again, I don't understand the benefit. What is Romney seeking?"

Fox Business Network anchor Liz Claman agreed, adding "it's a dangerous game that Mitt Romney is playing here because Donald Trump doesn't have a lot to lose by keeping this birther conversation alive…Mitt Romney and his people have to decide whether standing next to Donald Trump means more votes or fewer votes."

Trump revived the false claims about Obama's birthplace on Thursday, citing a discredited story about a literary agency that mistakenly listed that Obama was born in Kenya in a recently discovered catalog of clients that included the president.

"Look, it's very simple," Trump told The Daily Beast. "He said he was born in Kenya and raised in Indonesia… Now they're saying it was a mistake. Just like his Kenyan grandmother said he was born in Kenya, and she pointed down the road to the hospital, and after people started screaming at her she said, 'Oh, I mean Hawaii.' Give me a break."

The real estate mogul endorsed Mitt Romney in February. The pair will appear together on Tuesday in Las Vegas.

Trump himself repeatedly flirted with his own presidential run, regularly pushing the false "birtherism" claim that President Obama was not born in the United States.

The National Journal's Ron Brownstein argued that Romney's embrace of Trump is just part of a pattern we have seen throughout the entire primary season.

"I mean, Mitt Romney throughout the entire primary season has shown very little willingness to confront the right.  And there is a big portion of the conservative base of the party that does believe that Barack Obama was not born in the U.S.," he said. "And Romney has just seemed to be spooked throughout the whole process at the thought that the right will mobilize against him."

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