U.S. Rep. Diane Black was on her way back to Washington and almost at the security checkpoint in the Nashville airport when she realized she had left her driver's license at home in a pair of jeans.

She had her handgun permit, which included her photo, full legal name, date of birth and hologram with the state seal. But when the Republican from Gallatin, Tenn., presented the card to the security agent, she was informed a gun permit is not considered one of the acceptable forms of identification needed for boarding a plane.

"I was really taken aback," Black said. "I knew it had all of the information on it that is required for identification."

Black was able to go through security and get on her plane after showing the security agent her congressional voting card. But the experience left her curious about why some forms of identification are acceptable while others are not and made her determined to correct what she considered a double standard.

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