Rick Perry Once Forgot the Name of the Agency He May Lead

PHOTO: Former Texas Governor Rick Perry walks through the lobby on his way out of Trump Tower, Dec. 12, 2016 in New York.PlayDrew Angerer/Getty Images
WATCH Rick Perry's 'Oops' Moment at 2011 Primary Debate

Donald Trump is expected to choose a man to lead the Department of Energy who infamously forgot its name.

Former Texas Gov. Rick Perry is expected to be announced as Trump's pick for secretary of energy — a surprise to some, since Perry previously said he would eliminate the agency if he had his way.

During a presidential primary debate on CNBC in 2011, when then-candidate Perry was listing "three agencies of government, when I get there, that are gone," he was able to name Commerce and Education but blanked on the third, saying, "What's the third one there?"

When moderators asked him, after a pause, if he could recall the last one, he said, "I can't. The third one I can't. Sorry. Oops."

PHOTO: Republican presidential candidate Texas Gov. Rick Perry points his head as he speaks during a Republican Presidential Debate at Oakland University in Auburn Hills, Mich., Nov. 9, 2011.Paul Sancya/AP Photo
Republican presidential candidate Texas Gov. Rick Perry points his head as he speaks during a Republican Presidential Debate at Oakland University in Auburn Hills, Mich., Nov. 9, 2011.

The day after the debate fumble, Perry appeared on the "Late Show With David Letterman" to announce his "Top 10 excuses." The bit included reasons like "I thought the debate was tonight" and "I had a five-hour energy drink six hours before the debate."

While Perry's biggest gaffe during the 2012 race may have come from what he didn't say, it's something he did say during this election cycle that he may regret now.

In July 2015, Perry, at the time making a second bid for president, called Trump's candidacy "a cancer on conservatism" and hurled several other insults at his then-rival.

"He is without substance, when one scratches below the surface," Perry said during a speech at the Opportunity and Freedom PAC forum in Washington, D.C. "He offers a barking carnival act that can be best described as Trumpism, a toxic mix of demagoguery and mean-spiritedness and nonsense that will lead the Republican Party to perdition if pursued."

Despite these kerfuffles, Perry is expected to be named as Trump's choice for secretary of energy, senior transition officials told ABC News. Perry met with Trump at least twice in recent days.

If Perry is selected, his ties to energy companies will be in question as potential conflicts of interest. One of the clearest possible conflicts: his place on the board of directors of Energy Transfer Partners, which owns a subsidiary planning to build the Dakota Access Pipeline.

ABC News' Arlette Saenz contributed to this report.