After months of obstinate denial and simmering dismay, Republican elites are soberly coming to the conclusion that 2016 may be the year the raucous insurgent faction of the party finally topples the usually sturdy mainstream contingent in the presidential race.

The twin renegade candidacies of real estate mogul Donald Trump and junior Texas Sen. Ted Cruz are packing the potency and endurance to be plausible ultimate victors of the primary – an outcome deemed doubtful by wide swaths of GOP leadership just a few months ago.

The success of their campaigns is being enhanced by a divided slate of traditional candidates from the wing of the party known collectively in Washington – and derisively outside of it – as "the establishment."

There's also a palpable lack of urgency among party chieftains and mainstream campaigns to do anything about it. With just a month before balloting begins, there are few calls for unity and little sign of a grand coalescing in order to halt the march of the outsiders. Instead, there's a budding sense that if the voters decide 2016 is the year to tear the scab off, upend history and remake the party, so be it.

"There's no question he could be the nominee. Donald [Trump] has defied all political expectations for the last 150 days," says Scott Reed, the chief political strategist at the U.S. Chamber of Commerce and Bob Dole's 1996 campaign manager. "Say what you want about the process, it always does pick the best candidate in the end – for the cycle."

To be clear, there are still those who cling to the notion that it's more likely historical forces will eventually push the trajectory of the race back toward a mainline candidate. But gone is the widespread conviction that Trump or Cruz could not possibly stand in Cleveland in late July as the party's standard-bearer.

"Everything that's happened has defied expectations to this point, so it's just like, 'My gosh,'" says Florida Republican National Committeeman Peter Feaman, when asked for his primary forecast. "It's such a wild year. I've been wrong for months."

The candidacies of Florida Sen. Marco Rubio, New Jersey Gov. Chris Christie, Ohio Gov. John Kasich and former Florida Gov. Jeb Bush have not been most stifled by Trump or Cruz, but instead by each other.

Most Republican primary contests over the past two decades have featured a more conservative challenger attempting to upend an establishment favorite, from Pat Buchanan against Bob Dole in 1996 to Rick Santorum against Mitt Romney in 2012. Over time, it could again whittle down to that binary choice. But never has the establishment faction been more divided among so many options and without one who looks convincingly stronger than the rest by this late point in the race.

"I think it would be better if all the Republican players got behind one candidate. But that's what a democracy is all about. It's not a beautiful thing in form, it can be messy," says Bart Daniel, a Charleston, South Carolina, attorney who helped lead fundraising efforts for Sen. Lindsey Graham's unsuccessful campaign.

At this venture in the 2012 primary, the final national poll of the year, conducted by CNN, found Newt Gingrich and Romney knotted at 28 percent. Perhaps more strikingly, while Romney ceded the polling lead to several challengers during the fall of 2011, he always remained in double-digits and in second place.

In the 2008 cycle, the end of the year Pew Research Center poll pegged Arizona Sen. John McCain at 22 percent nationally, good enough for a 2 percentage point advantage. There again, the eventual nominee was in respectable standing, not dwelling in the polling basement.

The final national snapshot of the 2016 primary this year looks markedly different than years past. Combined, Trump and Cruz collect 57 percent of the vote in the CNN/ORC poll. Take Rubio (10 percent) and add Christie (5 percent) plus Bush (3 percent) plus Kasich (2 percent), and their sum doesn't equal even half of the two front-runners' combined total.

"Here's the difference," explains Richard Viguerie, a veteran leader of the conservative movement who supports Cruz. "As long as we can remember, the establishment was united behind one candidate, with 25 to 30 percent. This time the establishment's got four or five candidates dividing 25 percent of the vote."

"This year's somewhat different," concedes Sen. Lamar Alexander, a Republican from Tennessee who ran for president in 1996 and 2000. "The anti-establishment mood is all around the world – it's in Europe, it's in the United States. Usually you would look at one of these four to be the nominee – Bush, Rubio, Christie and Kasich – for their capacity to be president. But that's not the case today."

In a normal year, a widely respected third-term Republican senator might put his name behind one of those candidates, but Alexander seems unlikely to do so this time. "I think endorsements count for almost nothing these days," he says.

There is broad agreement that the first true test of the establishment's might will come in New Hampshire with the state's Feb. 9 primary, eight days after the first-in-the-nation Iowa caucuses.

Whereas the Hawkeye State's caucuses require a public pledge of support and tend to be dominated by evangelical and ideologically rigid voters, New Hampshire allows independents to participate in its private ballot primary, historically drawing a more centrist pool of voters.

With Cruz clutching what is perceived to be close to a lock on Iowa due to his polling, hard-line message matrix and well-oiled organization, the center-right fold of the party is already looking beyond that contest to the Granite State.

"Iowa's an aberration. Because it's a caucus state, it's not going to tell us that much," says former Wisconsin Gov. Tommy Thompson, who is backing Bush.

And yet there stands Trump, continuing to dominate polling in New Hampshire. What's unknown is how a loss in Iowa would impact his psyche and reputation going forward and what kind of momentum Cruz could generate coming off a likely victory.

"The question is going to be how does [Trump] react to losing Iowa? How does he react to being a loser? [What] if he goes postal, which he's more than capable of doing?" asks the Chamber of Commerce's Reed, who thinks a Trump victory in Iowa is impossible given the historical dominance of evangelicals there. "Trump has a chance in New Hampshire because they historically like to punish whoever came out of Iowa," he says.

That makes the scrum for second place there pivotal, with as many as five candidates clamoring to become the establishment alternative – unless, of course, it's Cruz who comes in second.

Christie, once dismissed due to scandal, is enjoying the best burst of media buzz due to his accessibility and visibility in the state. He's made 32 trips to New Hampshire since 2013, far more than any candidate of either party according to The Chase Presidential Tracker. But his weakness lies in a dependence on a single-state strategy and the fallout from taking a beating in Iowa.

"He will not be in the story coming out of Iowa – that's a danger. That's where the free media really comes in," notes Reed.

The biggest nightmare for the establishment in New Hampshire would be a muddled result reflective of the divided loyalties in the state, a scenario that remains in the cards.

"There's great potential you could have five or six candidates emerge from New Hampshire all within 1 percentage of [each other.] If I'm at 13 percent and the top guy is at 18 percent, I see this battle going on well into April and May," says Republican National Committeeman Steve Duprey, who has attended 30 candidate town halls this year.

"You're still going to have seven players going to South Carolina," predicts Thompson, citing the Feb. 20 contest that follows New Hampshire.

A prolonged scenario could benefit Trump and Cruz, who, with victories in their pockets, would turn to the slate of Southern primaries in March with a head of steam.

"If Cruz wins Iowa and Trump wins New Hampshire, there could be a rush towards Cruz by mainstream Republicans who are willing to accept Cruz as a flawed but legitimate alternative to Trump," says Dick Wadhams, a former chairman of the Colorado Republican Party. "Anecdotally, I hear that viewpoint from Republican friends of mine who are appalled by Trump and who really don't like Cruz but are starting to think he is looking awfully good compared to Trump."

Even longtime veterans of presidential campaigns differ greatly on how and when the field will winnow this time around, but many do see Rubio as a finalist. The 44-year-old, first-term Floridian could end up being the last great savior of the Republican hierarchy, just as he was billed to be when he first arrived on the scene.

"If I was going to invest my money I'd invest it with Trump, but my vote would go to Rubio," says former Texas Sen. Phil Gramm, who ran for president in 1996. "I just think he's got a Reaganesque quality to him. He can state strong positions and still smile. His optimism shines in an era where people are not very optimistic."

Viguerie, who is supporting Cruz, concurs: "I think by March or April it's going to be a two-person race and that's going to be Cruz and Rubio. The establishment's going to get behind Rubio to prevent a Trump or Cruz nomination."

But it may take several lumps before the establishment moves to panic mode. March 1 – the biggest delegate day on the calendar featuring a trove of Southern states – looks like prime picking for Cruz and Trump. Cruz has built one of the deepest organizations in those states and Trump has performed well in early polling. The question is whether the establishment can endure a month of stifling losses before they make their move.

"March 2 is the day the establishment wakes up and says, 'Holy s---, we got Cruz'. Then you'll see consolidation," predicts Reed.

Yet when it comes to Trump, there are flashes of a more accepting tone in the voices of unnatural sympathizers who have grown to respect what the reality show billionaire has already accomplished in tapping the raw vein of the American populace. It is begrudging respect meeting reality.

Says Gramm: "I disagree with a lot of what Trump is saying. Looking back on it now I have to give him his dues. He has spoken to a lot of frustrations that people like me weren't paying attention to. At the end of the day I think he will have contributed to our process. I wouldn't have said that six months ago, but I believe it now."

Adds Duprey: "In the Beltway crowd all these people are worried about Donald Trump. He's running a great campaign. It's not fake. He does have a ground organization. They're calling, they're dialing, they have volunteers – I've seen it. People who thought Donald Trump was a flash in the pan were obviously wrong."