The Senate Parliamentarian has ruled that President Barack Obama must sign Congress' original health care reform bill before the Senate can act on a companion reconciliation package, senior GOP sources said Thursday. The Senate Parliamentarian's Office was responding to questions posed by the Republican leadership. The answers were provided verbally, sources said. House Democratic leaders have been searching for a way to ensure that any move they make to approve the Senate-passed $871 billion health care reform bill is followed by Senate action on a reconciliation package of adjustments to the original bill. One idea is to have the House and Senate act on reconciliation prior to House action on the Senate's original health care bill. Information Republicans say they have received from the Senate Parliamentarian's Office eliminates that option. House Democratic leaders last week began looking at crafting a legislative rule that would allow the House to approve the Senate health care bill, but not forward it to Obama for his signature until the Senate clears the reconciliation package. Meanwhile, Senate Majority Leader Harry Reid (D-Nev.) moved Thursday to put Senate Republicans on the defensive over health care, sending a letter to Minority Leader Mitch McConnell (R-Ky.) in which he dared the GOP to vote against reform. Reid also defended the Democrats' use of reconciliation to get a final health care reform bill to the president's desk, noting that the bulk of health care reform was approved under regular order via the package that cleared the Senate on Christmas Eve. Reid also emphasized that Republicans have used the procedure several times over the years. However, Reid also promised in the letter that Republicans would have ample opportunity to amend the reconciliation package. "Reconciliation is designed to deal with budget-related matters, and some have expressed doubt that it could be used for comprehensive health care reform that includes many policies with no budget implications. But the reconciliation bill now under consideration would not be the vehicle for comprehensive reform — that bill already passed outside of reconciliation with 60 votes," Reid wrote to McConnell. "Reconciliation will not exclude Republicans from the legislative process. You will continue to have an opportunity to offer amendments and change the shape of the legislation. In addition, at the end of the process, the bill can pass only if it wins a democratic, up-or-down majority vote. If Republicans want to vote against a bill that reduces health care costs, fills the prescription drug donut hole' for seniors and reduces the deficit, you will have every right to do so," he said.