Story highlights Republicans are unanimous in their desire to "repeal and replace," but not unanimous on the details

The GOP can't lose more than two votes of its senators to pass the bill

Washington (CNN) Republicans are unanimous in their desire to "repeal and replace" President Barack Obama's signature health care law -- but they are already flirting with not having the 50 votes needed to pass the bill in the Senate.

Republicans have 52 seats in the Senate, meaning they can only afford to lose three members of their caucus before they cannot pass legislation without Democratic votes. (In the case of a 50-50 tie, the vice president casts the tie breaker -- presumably in favor of the GOP side.)

While only one Republican -- Kentucky Sen. Rand Paul -- has thus far signaled he might vote no on the Obamacare repeal mechanism currently moving through the Senate, potential flashpoints have already emerged that could jeopardize further votes.

House Speaker Paul Ryan's support of using the Obamacare repeal measure to strip federal funding for Planned Parenthood, an organization that provides abortions as part of its broader reproductive health care services to men and women, could cost the GOP two key votes.

That measure would likely pass in the House, but two pro-abortion rights GOP senators, Susan Collins of Maine and Lisa Murkowski of Alaska, won't commit to approving the bill with the Planned Parenthood provision in it.

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