WASHINGTON — U.S. House Speaker Paul Ryan said on Thursday he was willing to help Senate Republicans advance a chaotic effort to dismantle Obamacare by committing to House-Senate negotiation, while senators debated a pared-down repeal bill to get them to that point.The reassurances from Ryan presented the possibility that Senate Republicans in the wee hours of Friday may approve a bill that they do not want to become law - only so they can keep their effort alive and develop a different bill with the House.Ryan’s comments came shortly after three Senate Republicans threatened to oppose a so-called “skinny repeal” of Obamacare if they did not get assurances that it would not become law.Without committing to specifics, Ryan said his Republican-controlled chamber would consent to a conference negotiation, but stopped short of promising major changes and insisted that the Senate take the first steps on any new bill.“If moving forward requires a conference committee, that is something the House is willing to do,” Ryan said in a statement.