Members of the California State Assembly are allowed to change their vote on a bill--or cast it--after the bill has passed or failed. Many have done so thousands of times this year.

The rule allows members to change their vote after voting has officially closed, as long as it doesn't affect the outcome. They can also add votes late, after a bill has already been decided.

An analysis by the Associated Press found lawmakers take full advantage of the rule, switching or adding votes more than 5,000 times in 2012.

Berkeley Assemblywoman Nancy Skinner added 80 votes, but says she had good reason.

"You know, I was in the bathroom or I was in the Senate working a bill over on the Senate floor, or I was at a committee presenting my bill, so of course, I want to make sure that I cast my vote, so then I add on."

Skinner also withdrew seven yes or no votes so it looked like she didn't vote. She says the bills weren't ready.

"You've showed me you have the commitments that it will pass, so I'm giving you this courtesy, but I'm going to have the right to pull myself off because I don't think the thing's cooked yet," she said.

San Rafael Assemblyman Jared Huffman added 144 votes, but he says he rarely changes a vote.

"I think it is too easy to change votes, and it ought to be something that is more transparent,"  he said. "When someone changes a vote, the whole world ought to know."

The Associated Press found votes are more likely to be added or changed by Assembly members up for re-election, or on hot-button issues.

Wesley Hussey is an assistant professor of government at Sacramento State. He says Assembly members might vote with their party, then change their vote later to please constituents.

"But fortunately, since the rules don't allow votes to change the outcome of legislation, I think voters and California residents can feel a little more secure that there might be shenanigans going on, but not at an egregious level," Hussey said. 

Hussey says most states do not let Assembly members change votes.