The "defund Planned Parenthood" movement has a standard response to the question of where women would go if their local clinic closed: somewhere else.

"There are 13,000 community-based organizations that provide health services to women, 13,000 in this country," Jeb Bush said at an early Republican primary debate. "I don’t believe that Planned Parenthood should get a penny from the federal government."

Other Republicans make a similar claim. A spokesperson for Sen. Ted Cruz (R-TX) argued that Planned Parenthood's funding could be diverted to "community health centers and other entities providing health services without abortions." And on paper, it sounds plausible that 13,000 clinics might be able to absorb Planned Parenthood's 2.7 million patients who get government help paying for birth control and other reproductive health services.

But as the Senate votes to strip Planned Parenthood of millions in federal funding, a Vox review of academic research, recent Planned Parenthood closures in Texas, and interviews with half a dozen health policy experts suggests the opposite. Historically, researchers have found that when Planned Parenthood clinics close, other clinics do not step up to fill the gap. Meanwhile, when there are fewer reproductive health clinics available, women get less reproductive health care — from birth control to cancer screenings to STD testing and treatment. Unintended pregnancies would likely increase, too.

When Planned Parenthood clinics close, other providers don't step up

So while many politicians like to assert that women can "go somewhere else," the consensus in the literature shows a different picture. Higher-income women will find alternatives. But a sizable minority of Planned Parenthood's patients, particularly low-income women, would lose access to medical services.

Planned Parenthood is a major part of America's reproductive health network

Planned Parenthood plays a big role in women's reproductive health care in America for two reasons: It has hundreds of clinics, and those clinics tend to serve a higher number of patients than other health-care providers.

About one in six American counties — 491 counties in total — have a Planned Parenthood clinic. Taken together, they see about 2.6 million patients annually.

Planned Parenthood exists in many places where other family planning clinics don't: A new analysis from the Guttmacher Institute estimates that there are 103 counties in the United States where Planned Parenthood is the only provider of publicly funded contraceptives. In an additional 229 counties, Planned Parenthood serves the majority of women who are low-income and qualify for government help paying for birth control.

This relates to the other important fact to know about Planned Parenthood: It tends to serve way more women in public programs than do other places, like public health clinics or primary care doctors. They see, on average, 2,950 birth control patients per year, compared with the average of 750 seen at public health centers and 330 at federally qualified health centers.

To put it another way: Planned Parenthood clinics comprise only 10 percent of publicly funded contraceptive clinics — but see 36 percent of patients who use the government birth control programs. Their clinics have developed a specialty in this area, and are particularly tailored toward providing reproductive health care. The other clinics that see fewer birth control patients, however, don't have that specialty — and experts say they'd struggle to absorb additional patients.

"One of the arguments that has come up at congressional hearings is that you could take the money we spend on Planned Parenthood and push it to community health centers," says Kinsey Hasstedt, a public policy associate at the Guttmacher Institute, which supports abortion rights. "But with the reality of the caseload, and with millions of patients, we can't rely on community health centers to pick up the slack."

Texas cut Planned Parenthood out of its family planning networks — and women got less health care

Texas has for years now been a battleground for women's health. Its abortion restrictions are currently being challenged before the Supreme Court — and its own, successful work to defund Planned Parenthood has correlated with women receiving less reproductive health care in public programs.

In 2013, the Texas Women's Health Program began excluding Planned Parenthood from its network of clinics where low-income women could get contraceptives, STD screenings, and other reproductive health services. The Women's Health Program never paid for abortions.

"When Texas defunded Planned Parenthood, there was a lot of talk that it will be easy to fill the gaps and no one would lose services," says Leighton Ku, a public health researcher at George Washington University. "We called other clinics and asked them, 'If Planned Parenthood couldn't do this anymore, are you prepared to step up to the plate?' The answer, in the short run, was they couldn't do it. They just had limited capacity."

Since Texas defunded Planned Parenthood, fewer women get reproductive care

State data shows that without Planned Parenthood in the network, the public program provided care to about 9 percent fewer women than it did in 2011. In the West Texas region, women served by that program declined by 40 percent between 2011 and 2013 — the same year that Planned Parenthood closed two clinics in that area of the state.

"You had a provider shortage," says Joe Potter, a researcher who runs University of Texas's Policy Evaluation Project. As part of that project, Potter has worked with his colleague Dr. Junda Woo to study what happened to women seen at Planned Parenthood clinics in two Texas cities. That work, which is currently under academic review, shows that some users of injectable contraceptive (Depo Provera) were unable to find an alternative provider to continue with the shots shortly after Texas cut Planned Parenthood clinics out of network.

"There were barriers, Potter says. "Not everybody found a new provider, some who did had to pay copays or undergo new sets of exams. Those who went back to Planned Parenthood after the exclusion had to pay somewhere between $60 and $100 for their next shots."

Data from the Texas Health Department of State Health Services suggests that cutting Planned Parenthood out of the Women's Health Program may have helped reduce abortions in Texas. Elective abortion procedures fell 6.5 percent between 2012 and 2013 (abortions also fell 6 percent between 2011 and 2012, before Planned Parenthood lost funding, so it's hard to know whether the later decline is a product of the law or reflects a national decline in abortion rates).

It is possible that cutting off Planned Parenthood's government funding can reduce abortions – and that in the process, access to family planning services will be a casualty.

David Slusky, an economist at the University of Kansas, has studied the closure of family planning clinics in both Texas and Wisconsin, where Gov. Scott Walker cut reproductive health funds in a way that disproportionately affected abortion clinics like Planned Parenthood.

His work, published with University of Chicago's Yao Lu in the Journal of Applied Economics, isn't about Planned Parenthood specifically. It looks at an anonymous, national network of family planning clinics. Still, the findings are the same: When clinics close, not all women find a new provider. Some just get less care.

More specifically, Slusky and Lu show that increasing a patient's distance to a family planning clinic by 100 miles leads to an 11 percent decline in clinical breast exams and a 14 percent drop in Pap smears. Declines in care were even bigger among lower-income and less-educated women.

"Preventive care is all about reducing future harm to yourself," Slusky says. "So if you can't take off work to drive 100 miles each way, then you're not going to go, because it's not worth it. When access to care is such an issue, that could be a completely rational decision for even a forward-looking person."

If Planned Parenthood shutters, others fear a similar outcome

The Congressional Budget Office recently surveyed the existing literature on Planned Parenthood and estimated that if Congress did defund the group, somewhere between 5 and 25 percent of its clients — 130,000 to 630,000 women — would lose access to care.

What's more: CBO estimated in a separate report that defunding Planned Parenthood would cost the federal government $130 million over a decade, because it would reduce access to family planning services and increase unintended pregnancies.

There are some clinics that say they could step up to fill the gap Planned Parenthood would leave behind. The National Review recently pointed to Obria, a medical clinic that presents itself as a Planned Parenthood alternative, as one such example.

"These clinics and maternity homes have enormous power of persuasion in the abortion debate — simply because they exist," Erika Bachiochi wrote in that article.

There are other clinics like Obria that exist, but they are few and far between. And with Planned Parenthood serving more than 2.6 million women who receive publicly funded contraceptives, there simply aren't enough to fill the gap. That's the point the California Primary Care Association made in a recent letter to Congress.

"Eliminating Planned Parenthood from our state's comprehensive network of care would put untenable stress on the remaining providers," Andie Martinez Patterson, the group's director of government affairs, wrote. "We do not have the capacity for such an increase in care and building such capacity would require significant capital investment."