Janna Ryan, wife of Republican vice presidential nominee Paul Ryan of Wisconsin, waits for the start of the vice presidential debate at Centre College.

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Jill Biden, wife of Vice President Joe Biden, waits for the start of the vice presidential debate at Centre College.

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Vice President Joe Biden, left, and Republican vice presidential nominee Paul Ryan of Wisconsin shake hands during the vice presidential debate at Centre College.

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Vice President Joe Biden and Republican vice presidential nominee Paul Ryan of Wisconsin participate in the vice presidential debate at Centre College.

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Vice President Joe Biden makes a point during the vice presidential debate with Republican vice presidential nominee Rep. Paul Ryan of Wisconsin at Centre College.

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Vice President Joe Biden and Republican vice presidential candidate, Rep. Paul Ryan, R-Wis., shake hands before the start of the vice presidential debate, at Centre College in Danville, Ky.

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Moderator Martha Raddatz watches as Vice President Joe Biden and Republican vice presidential nominee Rep. Paul Ryan of Wisconsin participate in the vice presidential debate at Centre College, Thursday, Oct. 11, 2012, in Danville, Ky.

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Vice President Joe Biden answers a question as Republican vice presidential nominee Rep. Paul Ryan of Wisconsin listens during the vice presidential debate at Centre College.

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Vice President Joe Biden and Republican vice presidential nominee Rep. Paul Ryan of Wisconsin participate in the vice presidential debate at Centre College.

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Vice President Joe Biden answers a question during the vice presidential debate at Centre College.

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Vice President Joe Biden and Republican vice presidential nominee Rep. Paul Ryan of Wisconsin participate in the vice presidential debate at Centre College.

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Republican vice presidential nominee Rep. Paul Ryan of Wisconsin, right, listens to Vice President Joe Biden during the vice presidential debate.

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Vice President Joe Biden and Republican vice presidential nominee Rep. Paul Ryan of Wisconsin participate in the vice presidential debate at Centre College.

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Vice President Joe Biden and Republican vice presidential nominee Rep. Paul Ryan of Wisconsin participate in the vice presidential debate at Centre College.

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Republican vice presidential nominee Rep. Paul Ryan, of Wisconsin, right, listens as Vice President Joe Biden speaks during the vice presidential debate at Centre College.

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Vice President Joe Biden and Republican vice presidential nominee Rep. Paul Ryan of Wisconsin participate in the vice presidential debate at Centre College.

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Republican vice presidential nominee Rep. Paul Ryan of Wisconsin watches as Vice President Joe Biden answers a question during the vice presidential debate at Centre College.

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Vice President Joe Biden and Republican vice presidential nominee Rep. Paul Ryan of Wisconsin participate in the vice presidential debate at Centre College.

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Republican vice presidential nominee Rep. Paul Ryan, of Wisconsin, right, watches as Vice President Joe Biden, speaks during the vice presidential debate at Centre College.

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Republican vice presidential nominee, Rep. Paul Ryan, of Wisconsin, speaks during the vice presidential debate at Centre College, Thursday, Oct. 11, 2012, in Danville, Ky. (AP Photo/David Goldman)

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Republican vice presidential nominee Rep. Paul Ryan of Wisconsin answers a question during the vice presidential debate at Centre College.

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Vice President Joe Biden answers a question during the vice presidential debate at Centre College.

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Republican vice presidential nominee Rep. Paul Ryan, of Wisconsin, speaks during the vice presidential debate with Vice President Joe Biden at Centre College.

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Republican vice presidential nominee Rep. Paul Ryan of Wisconsin answers a question during the vice presidential debate at Centre College.

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Vice President Joe Biden and Republican vice presidential nominee Rep. Paul Ryan of Wisconsin participate in the vice presidential debate.

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Vice President Joe Biden and Republican vice presidential nominee Rep. Paul Ryan of Wisconsin participate in the vice presidential debate.

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Republican vice presidential nominee Rep. Paul Ryan of Wisconsin answers a question during the vice presidential debate.

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Republican vice presidential nominee Rep. Paul Ryan's wife Janna, left, shakes hands with Jill Biden, wife of Vice President Joe Biden, following the vice presidential debate at Centre College in Danville, Ky.

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