President Barack Obama is calling the latest criticism from Republicans Mitt Romney and Paul Ryan "dishonest."

Romney and Ryan have accused Obama of raiding more than $700 billion from the Medicare trust fund to help pay for his health care overhaul. Obama told a crowd in Iowa today that he has "strengthened Medicare." He says his Republican rivals are "throwing everything at the wall to see if this sticks."

Obama didn't respond directly to Romney's charges that Obama's campaign is driven by "division and attack and hatred" and that he "would do anything in his power" to remain in office.

But Michelle Obama defended her husband as she introduced him at a rally in Dubuque, saying "we all know what he stands for."

The first lady has joined the president for the last day of his three-day bus tour of Iowa.


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