Jonathan H. Adler considers the question:

A final step the administration could take would be to enhance access to contraception by making all forms of oral contraception available over-the-counter without a prescription (and not just “Plan B”). While this would not make contraception “free” it would reduce the cost, and help alleviate some of the non-monetary obstacles women face. As Adrianna McIntyre notes, cost is hardly the only (or even the largest) obstacle working women face when it comes to obtaining contraception. Making oral contraception available OTC might not help the 3-4 percent of women who use IUDs, but it would nonetheless expand access to contraception as a practical matter, particularly for the working poor. It also has the support of some prominent conservatives and would largely eliminate the cultural conflict engendered by the mandate.

One such conservative is Philip Klein:

Philosophically, it’s consistent with limited government principles. It removes unnecessary government regulations and increases choice. It doesn’t impose new burdens on businesses or religious institutions, nor does it require an increase in government health care spending. And politically, it would also be beneficial to Republicans. It would make it a lot more difficult for Democrats to portray the GOP as being only interested in obstructing Democrats rather than supporting their own ideas, and harder to accuse Republicans of being broadly against access to birth control. Instead, it would allow Republicans to go on offense, and show that Democrats are the ones who want to play politics with birth control.

Ben Domenech, another conservative, runs through the counterarguments:

There are a number of objections to [OTC birth control], but I find them to largely amount to unconvincing paternalism.

The chief argument advanced is that standard oral contraceptives mess with hormones and have all sorts of side effects. This is, of course, true! But: dangerous side effects are rampant within all sorts of other over the counter drugs. Women can think for themselves and make decisions with their doctor and pharmacist about what drugs they want to take – and the evidence shows they are good at self-screening. In fact, it would actually increase the ability to mitigate and respond to unanticipated side effects, since changing tracks will no longer require a doctor’s visit and getting a new prescription. Assuming that women won’t or can’t take responsibility for themselves to consult with a doctor unless required to by arbitrary government policy is absurd.

Allahpundit spotlights one of the idea’s most vocal supporters:

Bobby Jindal, who’s wooing religious conservatives ahead of 2016, has been pushing [the OTC pill] since 2012. … Congress could, as Jindal suggests, even adjust Health Savings Accounts so that they include OTC medicines, which would further reduce the financial burden. And politically, it would complicate the Democrats’ dopey “war on women” messaging by decoupling the contraception debate from the debate over abortion. How do you push a “Republicans don’t believe in reproductive freedom” message if GOPers like Jindal want to make the pill OTC?

But the best endorsement comes from the OCOG:

In the United States, the proposal to sell oral contraceptives over the counter has been endorsed by the premier body of relevant experts, the American Congress of Obstetricians and Gynecologists. Ultimately, though, the decision will be made by the FDA.

So why the holdup? Elizabeth Nolan Brown has a must-read: