It's possible, just possible, that the final battle to become the 2016 GOP standard-bearer will come down to a pair of first-generation Cuban-American, first-term senators. Yes, I'm talking about the same Republican Party that has proven so incompetent in reaching out to Hispanic voters that it followed up its 2012 post-mortem determination to get better at it by, arguably, getting worse. Not that a final showdown between Sens. Ted Cruz of Texas and Marco Rubio of Florida will necessarily help on that score, but more on that later.

How does this scenario play out? It starts with the assumption that the three current front-runners, according to RealClearPolitics' average of polls – former reality TV star Donald Trump (23.3 percent), neurosurgeon Ben Carson (16.3) and former Hewlett-Packard CEO Carly Fiorina (11.8) – will all fade.

There are good reasons to expect this both in general and specific to each candidate. Trump's have been repeated and recycled for months: He's an egomaniacal, serially insulting, loud-mouth and while that might not sink him in a GOP primary, his ideological incoherence and departures from standard Republican policy positions probably will. After being endlessly foretold since his announcement the great Trump decline appears to finally be under way: He still leads but his share of supporters has dropped from 30.6 percent on the night of the second debate to 23.3 percent, more than a 7 percentage point drop in two weeks. That is, as the man might say, yuuuuge.

Indeed, as a broader matter both Carson and Fiorina are still in what political scientists John Sides and Lynn Vavrek identified in their book "The Gamble: Choice and Chance in the 2012 Presidential Election" as the discovery, scrutiny and decline phases of presidential campaigns. The first phase generally coincides with a polling uptick and flattering media coverage, but "early success has its burdens," Vavrek noted this spring. "For most candidates, the scrutiny reveals some weakness in the candidate – a past action or an undesirable personality trait – that leads to a decline in the polls."

Relatedly, neither Carson nor Fiorina (nor, for that matter, their campaigns) have been seriously tested the way legitimate first-tier candidates are, either by the media, by their adversaries or by outside groups trying to influence the nomination process. Running for president is tougher than it looks and political neophytes face the double challenge of learning to run for office whilst seeking the land's highest office. Imagine a baseball player making their professional debut in the major league playoffs. Not for nothing is the list of presidential nominees filled almost entirely with experienced politicians; the only modern exception is Dwight Eisenhower whose resume included being supreme allied commander during the Second World War.

Maybe this is the year that an outsider upends the system and the political laws of physics stop working, but I feel safe betting that this year's outsiders will join the likes of Herman Cain, Wes Clark, Steve Forbes, Pat Buchanan and Pat Robertson as notable also-rans. But the Trump-Carson-Fiorina axis does illustrate that the angry, anti-establishment section of the GOP electorate is alive and well. And each of the last four sets of contested Republican primaries (going back as far as 1996, when Pat Buchanan won New Hampshire and exhorted his supporters to "mount up … and ride to the sound of the guns") has boiled down to an anti-establishment candidate against an establishmentarian. So where do the disaffected GOP voters go?

Of the potential anti-establishmentarians, former Arkansas Gov. Mike Huckabee had his turn as last-outsider-standing in 2008 and former Pennsylvania Sen. Rick Santorum had his in 2012. Kentucky Sen. Rand Paul took time out of his presidential campaign this week to work on his simultaneous senatorial re-election while one of his super PACs abandoned him. Who does that leave? Cruz, who has been auditioning for the role since he joined the Senate, has transparently positioned himself to scoop up the angry Trump voters when he folds and also has a bigger share in the average of polls (6.2 percent) as Huckabee (3), Paul (2.3) and Santorum (0.5) combined. If there's an anti-establishment establishment, Cruz is its candidate.

What of the actual establishment? Former Florida Gov. Jeb Bush had been its presumptive favorite, but his candidacy was built on inevitability – not only would he shock and awe the field with his fundraising prowess but he was the more politically adept Bush brother, fluent in both policy and Spanish. But he's proven to be the bumbling Bush, unprepared for obvious questions when they involve his presidential family members and generally looking like someone who last ran for office more than a dozen years ago. Stripped of his veneer of inevitability, Bush' weaknesses have been laid bare: He's a bad candidate, he's out of sync with his party on issues like immigration and education and he bears a name that inspires less confidence than hostility. His poll numbers have tumbled accordingly, dropping from a high of 17.8 percent in mid-July to 9 percent now.

To whom else might the establishment turn its lonely eyes? By all rights Ohio's John Kasich – the popular governor of the most important swing state in the union – should be leading the GOP field, but he has aroused the party's ire, most notably by not only accepting the Obamacare Medicaid expansion, but by being sanctimonious about it. New Jersey Gov. Chris Christie has earned a reputation as a bully, which doesn't wear well, and never recovered from the Bridgegate scandal. Sweep aside the polling detritus (former New York Gov. George Pataki and Louisiana Gov. Bobby Jindal each sit at or below 0.5 percent, South Carolina Sen. Lindsey Graham sits at 0.2 percent and former Virginia Gov. Jim Gilmore has been consigned to oblivion, not even appearing on the list) and you're left with Rubio. The first-term Florida senator is experiencing a boomlet and recently inched past Bush in the polls (by a fraction of a percentage point, meaning that they're functionally tied). As a fresh face and – bonus! – a Hispanic, Rubio would be an appealing choice against Hillary Clinton, who has seemingly been part of our politics forever.

Rubio versus Cruz would set up a striking optimism-versus-anger choice of the GOP. But party leaders should temper any hopes that either man could prove to be an instant balm for the party's problems with Hispanics. The truth is that Latinos are not monolithic; and Mexicans (who make up 64 percent of Hispanics in this country) and Puerto Ricans (the second largest subgroup, with 9.4 percent), for example, may not feel any special kinship with a Cuban. Rubio or Cruz might shore up waning GOP support among Florida Cubans but shouldn't assume they'll have a great effect in places like Colorado, New Mexico and Nevada.