An expected vote on a sweeping package of tax cuts and reforms failed to materialize on Thursday evening in the U.S. Senate, as GOP leaders were forced to renew negotiations with a small group of Republican Senators, following a review which showed that the tax cuts would not spur anywhere near enough economic growth to pay for themselves, instead adding $1 trillion to the federal deficit over ten years.

Republicans had thought they were cruising along to victory in the Senate, planning for a late night vote to approve a GOP tax reform bill - but as the hours dragged on, they didn't have the deals in place to finalize that measure, as Senate Majority Leader Mitch McConnell set up a Friday session, where the GOP will try again.

"They still don’t have enough votes to pass this awful bill," said Sen. Dianne Feinstein (D-CA).

Several items were causing trouble for Republicans - as like during the debate over how to overhaul the Obama health law - GOP leaders were just trying to get to 50 votes, so the Vice President could break a tie.

First, a review by Congressional number crunchers showed the GOP plan would still add just over $1 trillion to the national debt over ten years, even when dynamic scoring was used, to factor in extra economic growth spurred by tax reductions.

The review by the Joint Committee on Taxation, differed from one done by the Congressional Budget Office, which had found the bill would increase the deficit by $1.4 trillion over ten years.

Then, the Senate Parliamentarian ruled against one GOP idea for a "trigger," which would have triggered tax increases in later years to bring in more revenue, if the plan failed to generate enough tax receipts in the future due to lower than anticipated economic growth.

"My Republican colleagues are scrambling," said Sen. Richard Blumenthal (D-CT), "searching and scrambling for a so-called trigger."

But indications were the GOP was looking at much more than just the trigger, trying to forge even more last minute deals, as there is still no 'final' bill language for either party to evaluate.

Earlier in the day, there had been promising signs - Sen. John McCain (R-AZ), who torpedoed the health care plan back in late July, said he was on board with tax reform.

"I believe this legislation, though far from perfect, would enhance American competitiveness, boost the economy, and provide long overdue tax relief for middle class families," McCain said.

But then on the floor, there was suddenly trouble from a trio of GOP Senators - Sen. Bob Corker (R-TN), Sen. Jeff Flakes (R-AZ), and Sen. Ron Johnson (R-WI) - as they held up a vote for nearly an hour, while about a dozen Republicans haggled over different tax plans.

Outnumbered, Democrats could only stand on the sidelines and appeal for the GOP to reach out across the aisle, something that seemed unlikely.

"This bill is too important to rush – we need to get it right," said Sen. Angus King (I-ME), an Independent who sides with Democrats in the Senate.

"The tax bill before us is not for the middle class," said Sen. Bill Nelson (D-FL).

It was not readily apparent what Republicans would change in their bill, or if they would be able to forge a final deal on Friday. And at this point, there is still no actual final bill.

"Read the bill. Read the bill," mocked Sen. Brian Schatz (D-HI), invoking a favored line of Republicans.

"Every Senator should be asked tomorrow if they’ve read the bill," Schatz tweeted late on Thursday night.