One key committee at the 2016 Republican National Convention will determine whether Donald Trump and Ted Cruz supporters or the GOP leadership has the advantage in choosing the next nominee.

The rules committee's makeup and decisions have shaped the presidential race before, but play an even bigger role at a contested convention in Cleveland, GOP observers said.

Republican National Committee member Morton Blackwell, who has attended rules meetings at every convention since 1972, said he believes the outcome of the last contested convention in 1976 hung in the balance of the rules committee.

According to Blackwell, Ronald Reagan's delegates in the rules committee sought to force President Gerald Ford to name a vice presidential pick before the men delivered nomination speeches.

"That was something that Ford did not want to have to do because he had half-a-dozen leaders, had leaders of half-a-dozen states, in front of whom he was dangling the possibility that they would be his running mate," Blackwell said.

Those leaders were the gatekeepers of scores of delegates that could have shifted the balance of power in 1976, and Blackwell said, "If we had passed that rules change, I think Reagan would have been nominated in 1976. And it was a very close vote."

Blackwell said it's certainly possible that the 2016 nomination could turn once again on the minutiae ironed out by the rules committee.

The fault lines that will divide the delegates have already begun to reveal themselves. Curly Haugland, an outspoken 2016 rules committee member from North Dakota, has attracted attention for arguing that the Republican Party will pick the next nominee not the voters.

In an interview with the Washington Examiner, Haugland argued that there, "can be no presumptive nominee before the convention" this summer because the delegates do not know who is eligible.

"The media is trying to convince us, the cable networks are trying to convince us that it's based on the primary vote and that's a whole different animal. The primary votes are not solid," Haugland said. "There's all kinds of potential slippage in those primary votes based on various challenges that could be made or various other interpretations. For instance, 'winner-take-all,' I don't think will stand up personally at the convention. So those surplus delegates allocated by a winner-take-all I think are all subject to question."

While Blackwell disagrees with Haugland's assessment, Haugland will likely find allies in the party establishment who drove the implementation of the rules it now wishes to ignore. Former New Hampshire Gov. John Sununu, the chair of the 2012 rules committee, told CNN in a recent interview that the ties that bind delegates to a particular candidate may be negligible by the time the party hits the convention floor this summer.

"Even in the first round, many delegates can vote for anyone," Sununu insisted. "And not every delegate is firmly bound."

Sununu insisted that "delegates can start voting for [House Speaker] Paul Ryan at any time," despite the Republican National Committee's recent statements that "upwards of 90 percent" of delegates are bound to start the convention.

In a recent Friday afternoon briefing, RNC officials sounded confident that the rules guiding the 2016 convention would change before it begins. Rule 40, which governs the presidential nominating process, has been subject to persistent scrutiny and suggestions that it may be rewritten.

Other guidelines offered by the RNC's rules suggest that rule 40 is merely " temporary," and subject to change, but doing so now may threaten the viability of the party. Subsection 'b' of the rule states that a nominee must demonstrate the support of a majority of delegates from eight or more states. Before the 2012 convention, only five states delegates' support was required.

Both Trump and Cruz have campaigned with the goal of exceeding the eight-state threshold, and altering the rule to accept additional competitors would irrevocably anger Cruz and Trump supporters.

Steve Scheffler, a 2016 rules committee member from Iowa who also served on the 2012 committee, said he fears any rule change that would allow a nominee who has not been vetted by voters to secure the nomination.

Still, Scheffler said he was not a fan of the eight-state threshold implemented at the 2012 convention by Mitt Romney's delegates, which he described as an attempt to besmirch Texas Rep. Ron Paul's supporters.

"I don't know where I'm at on that. I would love to change it back, but the last thing we can ill afford is a war or going out of the convention divided," Scheffler said. "[T]he Romney people should have thought about the ramifications of what they were trying to ram through because they wanted to make a point of sticking their poker in the eyeball of Ron Paul liberty people. And again, I wasn't a Ron Paul liberty person."

What the 2016 rules committee will ultimately decide remains unknowable, as many of the committee's members have not yet been selected. But the battle lines between Trump and Cruz delegates and the party establishment could be defined later this month.

If the party's establishment decides it wants to change the convention rules, it would likely do so at its spring meeting in Florida, according to Blackwell. Blackwell noted that RNC chairman Reince Priebus has "a supermajority" on the standing rules committee, and that advantage will likely change when the GOP gathers in Cleveland for a convention filled with Trump and Cruz delegates.

"Reince has the votes to do that if he decides to do it that way," Blackwell said. "And don't you believe anybody who says—if it does happen that way—that Reince didn't decide to do it that way."

Blackwell sought to change rule 40 against the party establishment's wishes in 2013 and tried to modify it in January 2016, but failed in both efforts. He said he thinks it's too late to make such changes now and added that the changes would be both unfair and catastrophic to the party. It's for this reason that Blackwell said he's not sure "Priebus is prepared to pull the trigger on such a battle" that could end the party.

"They've laid the groundwork for it, but there's been no decision as far as I know to pull the trigger," Blackwell said.

If the RNC fires the opening shot, chaos will ensue. Craig Shirley, a presidential historian and Reagan biographer who studied the brokered 1976 convention, told the Examiner that "there's always the chance of violence" at the upcoming convention, but the "good news is it's probably going to be the most-watched Republican convention in a long time."

"You are going to see something dramatic and historic in Cleveland because power as we speak is being drained away from Washington," Shirley said. "For the first time in a long time, the consultants are not going to be running this thing."

As to who will run the convention, Shirley anticipates anarchy.

"It's the wild wild West, is what it is," he said. "The dirty little secret is that the first rule of the convention is there's no rules."