Did Cheney nod off during Bush’s farewell address?

Last night during PBS’s coverage of President Bush’s farewell address to the nation, for a brief moment, the camera panned to Vice President Cheney, who appeared to momentarily doze off. But it seems that he quickly caught himself and then sat upright in his chair. Watch it:

If so, it wouldn’t be the first time Cheney’s boredom got the best of him.