Bart Stupak wants to radically change the nature of even private insurance funding of legal abortion services and is threatening to bring down the entire health care bill in the House if he doesn’t get his way. But according to one of America’s largest pro-choice groups, it’s completely unclear if he has the votes or even if abortion is driving the opposition.

As Jane Hamsher explains, Stupak has begun to claim that he has enough votes to “take down the rule” on the House health care bill. Basically, Stupak wants an amendment to the bill that would say that any plan selling in the exchange cannot offer to cover for abortion services if they accept public subsidies from anyone. That means that if a private company selling insurance to people in the exchanges gets just one low-income individual who signs up with them, they would be banned from covering reproductive choice.

It would be “a radical departure from current practice,” according to Donna Crane, policy director for NARAL Pro-Choice America. Currently, 87% of all private insurers offer coverage for abortion services, including the health plan that covers Focus on the Family, and this bill would dictate to them what coverage they would be barred from offering. Basically, individual and small-group subscribers would not have the same access to coverage which people who get coverage through an employer would. “It’s an abuse against private coverage, private people and private choice,” Crane said, going far beyond what kind of restrictions come under the Hyde Amendment.

The Speaker is likely to bar that amendment from ever coming to the floor. If it did, it would probably pass, given that there is still basically an anti-choice majority in the House of Representatives. Therefore, Stupak has decided that he would “take down the rule,” or gather a group to vote against the initial rule from coming to the House floor, the key test vote at the beginning of the process. Stupak says he has the votes (he would need 39 Democrats, as all Republicans can be expected to vote against the rule) to pull this off.

Similarly, if the House relented and this language did get into a manager’s amendment of the House bill, which Steny Hoyer suggested today, it runs the risk of blowing up the entire health care bill, as pro-choice Democrats would begin to oppose it in droves. This makes the politics of this extremely tricky.

But does Stupak actually have the votes? Stupak has sent several letters demanding that his language on abortion funding be inserted into the bill, in place of the compromise amendment submitted by Lois Capps that would let private companies make their own coverage decisions in this area, and separate subsidy money and private money to keep in the spirit of the Hyde Amendment. In NONE of those formal letters, Crane said, has Stupak threatened to vote against the rule explicitly. Crane said her organization doesn’t have a handle on just how many members Stupak has agreeing with him to take down the rule, but she believes it’s not as many as he claims.

Indeed, Stupak might be claiming support from those Democrats opposed to the current bill for other reasons. There are a host of Democrats with concerns about the bill. Some want an amendment on Medicare + 5% rates for the public option. Some want the state single-payer amendment, allowing states the ability to set up their own programs. Immigrant rights advocates want better language on undocumented workers and legal immigrants having access to the exchanges with their own money. Combined, all of these groups might have enough strength to block the bill. But Stupak isn’t controlling all of these members.

And Stupak may be picking up support from members who want a good reason to blow up the health care bill, which they simply don’t want to support for whatever reason. They can use the abortion question as a fig leaf to hide an actual agenda of protecting insurance companies or simply opposing reform.

NARAL has been working an inside/outside strategy to stop Stupak’s gambit. They have generated 150,000 messages to Congress from their membership in the past month, and they are lobbying “office by office” to explain the practical, radical effect of Stupak’s amendment, and how it doesn’t match his own rhetoric on it. This has been “painstaking and challenging” work, according to Crane, and because Stupak could be bluffing, it’s hard to know whether or not to call that bluff.

The White House has generally been supportive of the current compromise language in the bill. But Crane did not know whether the White House was actively supporting the language and leaning on those Democrats like Stupak who oppose it. A message to the White House was not immediately returned.