RALEIGH, N.C. — A House Democrat says she voted mistakenly to override Gov. Beverly Perdue's veto of a bill that authorizes natural gas drilling in North Carolina but was told she couldn't change it because the outcome would have changed.

Rep. Becky Carney of Charlotte says she pushed the green button at her desk Monday night to vote to override the vote before realizing she wanted to vote red, or "no."

Her "yes" vote made the tally 72-47 – just above the 60 percent majority required for the override. Changing her vote would have reduced the majority below 60 percent.

"I made a mistake, and I tried to get recognized to change it as people had been doing all night on other bills, and it was too late because it changed the outcome of the vote," Carney said.

House rules allow members to change their votes as long as it does not affect the outcome of a bill. They do that a lot, pushing the wrong button and then changing their votes later.

Because Carney's vote did affect the veto override, House Majority Leader Paul Stam said her intent to vote differently doesn't matter.

"That doesn't count in legislation. It's what you actually, how you actually vote, not how you wished to vote," said Stam, R-Wake.

Carney could have asked for that rule to be suspended, but she never got the chance. Stam used a parliamentary move called a clincher to make sure she couldn't change it, and House Speaker Thom Tillis defended the maneuver.

"I think the member was well aware of how to vote green or red. For whatever reason, maybe it was a mistake, maybe she decided to change her vote. We can't do that," said Tillis, R-Mecklenburg.

House Minority Leader Joe Hackney criticized the move.

“Failing to recognize Rep. Carney for a motion and then foreclosing the possibility with the clincher motion is 'gotcha' politics in the legislative process,” Hackney, D-Orange, said in a statement.

Carney had voted earlier against the legislation, which opens North Carolina to gas exploration, including a controversial drilling method known as "fracking," as early as 2014. She said she feels terrible about her error but acknowledged the bill passed legally, although late-night, end-of-session votes don't help the situation.

"I feel rotten and I feel tired, and I feel mistakes are made constantly when people are tired and under the stress of people pushing to get out of here," she said.