Republicans have until Sept. 30 to repeal Obamacare with only 51 votes in the Senate under the current budget resolution, further complicating the GOP's attempts to try again after a failed attempt in late July.

The Senate Parliamentarian ruled on Friday that the procedural tool called reconciliation, which Republicans hoped to use to bypass a filibuster in the Senate, expires on Sept. 30. Reconciliation allows a Senate bill to be advanced with only 51 votes instead of the 60 votes that are usually needed.

The GOP passed a budget resolution back in January that sets up the instructions on how to pass a healthcare bill through reconciliation. The procedural tool has some restrictions for using the budget pathway, including that legislation must slightly reduce the deficit and include only items that impact budget and spending levels.

But that resolution and reconciliation instructions expire on Sept. 30 at the end of the federal fiscal year, which means the fast-track tool for passing Obamacare repeal also expires then.

To continue to use reconciliation past that deadline, Republicans would have to pass a new budget resolution after Sept. 30.

Obamacare supporters cheered the Senate Parliamentarian's determination.

"Now that the parliamentarian has determined that Senate Republicans cannot use reconciliation instructions to repeal the Affordable Care Act beyond this fiscal year, we need to work together to expand, not cut, healthcare for millions of Americans who desperately need it," said Sen. Bernie Sanders, I-Vt., ranking member of the Senate Budget Committee.

It appears doubtful that Congress will be able to pass Obamacare before the Sept. 30 deadline, which is also the deadline to fund the government and raise the debt ceiling. Congress is also expected to debate a major aid package for the victims of Hurricane Harvey.