In Oklahoma, half of its women legislators aren’t running for re-election this year because they're term-limited out. That rate may seem high, but in a state that ranks 49th for the percentage of women currently serving in the state legislature, it doesn’t take a lot to get there.

“Our numbers to begin with are very low,” said Cindy Simon Rosenthal, director of Oklahoma University’s Carl Albert Congressional Research and Studies Center. “This is a major turnover of women in the legislature.”

In total, eight women are leaving -- seven because their terms are up and one because she is running for another office and would vacate her seat if successful.

When term limits were implemented in the early 1990s, the policy was billed, among other things, as a way to get more women elected to the legislature. The idea was that term limits would periodically force open races, where women candidates have historically fared better.

But in the early 2000s, it became clear that term limits were not the panacea for increasing women’s representation in politics. Since they were passed in Oklahoma and a number of other states in the 1990s, the level of female representation in state legislatures has stayed at roughly 25 percent.

Part of the reason term limits didn't work, said Debbie Walsh, the director of the Center for American Women and Politics at Rutgers University, is that they led to another problem. "The challenge became recruiting enough women because ground was lost when women were kicked out because of term limits," she said.

And women do need to be recruited. A widely cited 2013 report from American University indicates that women are less likely to seek political office than men, even if they have similar resumes.

But with term limits, recruitment efforts turn into a game of keep up. Take Michigan. In the late 1990s, half of the 31 women serving in the legislature were going to be term-limited out. The Michigan Women's Campaign Fund hired former legislator-turned-political-consultant Maxine Berman to head up a massive recruitment effort to find women to run not just for those seats but for all the open seats. All told, women ran for more than two dozen seats in 1998. The result for all that work was achieve the status quo: Women didn’t lose any ground, but they didn’t gain any either.

The idea of getting more women in politics and leadership positions is about more than just parity, It’s about getting different points of view and life experience in the State House as well, said Oklahoma State Sen. Stephanie Bice, a first-term senator who was encouraged by her predecessor to run for his seat. “There are things that perhaps our male colleagues don’t think about,” she said.

There's some good news for Oklahoma’s State House prospects. This year’s controversial debate in the legislature over state budget cuts and what some see as an attack on public schools in favor of charters has led to an unprecedented number of people, including women, filing to run for state office. In fact, women are on the ballot in 46 House races and five Senate races. But, notes Oklahoma University's Rosenthal, in just four of those races do the number of female candidates at least equal the number of male candidates, “meaning they have at least a 50/50 shot” of winning.

“Term limits have not proven to open up the system,” said Rosenthal, adding that Oklahoma’s women could lose ground this election. “Come November a lot of the women running in these 20 open districts might end up on top, but that would be pretty unprecedented.”