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Charles Krauthammer said that on the topic of Hillary Clinton's health, the "original sin" is that the Clintons never adequately explained the former secretary of state's debilitating concussion.

"They never really explained it. Nobody went into it," he said, noting that it was "severe" enough for Clinton to invoke it during her FBI interrogation as an excuse for why she couldn't recall key briefings.

He said he understands why people are now speculating about Clinton's health after she had a coughing fit on the stage in Cleveland.

"They are secretive. They cover stuff up. And they never adequately explained what happened when she had the concussion."

Watch the commentary above.

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