Senate Parliamentarian Alan Frumin on Monday heard arguments for and against a Republican challenge to the health care reform reconciliation package, but he did not immediately issue a ruling. Additional Republican challenges to the Democratic reconciliation package will be made this week, a GOP aide confirmed.

Democratic and Republican Senate staff met with Frumin behind closed doors Monday afternoon, with Republicans arguing that one provision of the reconciliation bill violates Section 310g of the Budget Act and should result in the entire package losing its reconciliation status. Democratic staff made the opposing argument.

After considering both sides, Frumin is expected to rule, although the timing of his decision is unclear. Section 310g prevents reconciliation legislation from impacting Social Security, and the GOP plans to argue that a provision in the bill dealing with excise tax on expensive “Cadillac” insurance plans does just that.

Meanwhile, Republican Senate staff is expected to make additional arguments, including that various provisions of the reconciliation package violate the so-called Byrd rule and should be stripped from the bill. Any change to the reconciliation package in the Senate would require that it be sent back to the House for a revote.

Should the bill lose its reconciliation protections, it would be subject to a filibuster and no longer be able to pass with just 51 votes. The Democrats would need to muster 60 votes to overturn any budget point of order upheld by the Parliamentarian, a difficult threshold to meet given that the Senate GOP Conference has already pledged to remain united on budget points of order. The House on Sunday night cleared the Senate-passed health care reform package and companion reconciliation legislation, which is intended to make key adjustments to the underlying, $875 billion Senate bill.