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Former defense secretary Donald Rumsfeld on Monday attacked the Obama administration for failing to secure a status of forces agreement with Afghanistan President Hamid Karzai.

Rumsfeld, speaking on Fox News, said even a "trained ape" could do better.

"A trained ape could get a status of forces agreement," Rumsfeld said. "It does not take a genius. And we have so mismanaged that relationship."

Rumsfeld noted that the United States has such agreements with more than 100 other countries. Such an agreement would allow the United States to station military forces in Afghanistan for years to come.

Karzai recently voiced support for Russia's annexation of the Crimean peninsula in Ukraine -- a significant blow to U.S.-Afghan relations. Rumsfeld said he understands Karzai's increasingly antagonistic relationship, given the Obama administration's treatment of him.

"United States diplomacy has been so bad -- so embarrassingly bad -- that I’m not the least bit surprised that he felt cornered and is feeling he has to defend himself in some way or he’s not president of that country,” Rumsfeld said.

Rumsfeld said the Bush administration had a "first-rate" relationship with Karzai and that it has gone "downhill like a toboggan" since Obama took over.