Your Republican presidential field, minus the guy in the glasses. (AP Photos)

The 2016 presidential nomination campaigns have been lively, especially on the Republican side. Unconventional candidates, including Donald Trump, Ben Carson and now Carly Fiorina, have made a big splash in the polls. Republican elites have also atypically failed to coalesce around a more conventional candidate so far. Every campaign brings its surprises. Yet it would be a mistake to react to these developments over four months before the first vote is cast by inferring that the nominating system has changed in important ways.

On Sunday, the New York Times’s Adam Nagourney and Jonathan Martin suggested that the modifications to the rules Republicans adopted after 2012 leave the GOP vulnerable to Trump, a prospect that fills many Republican operatives with dread. Nagourney and Martin write, “If Mr. Trump draws one-third of the Republican primary vote, as recent polls suggest he will, that could be enough to win in a crowded field.” These authors also report that Republicans worry about an open convention.

It is far from clear that Trump will retain his current level of support. The real estate mogul’s support dropped in the wake of Wednesday’s debate, according to the most recent CNN poll, which was released shortly after the NYT article appeared.

Moreover, the poll reveals that the polarizing New York billionaire is few voters’ second choice for the nomination. So we may have reached “Peak Trump.” Trump’s trajectory remains uncertain. Yet we can say that retaining the support of one-third of GOP voters is unlikely to result in victory for Trump or an open Republican convention next summer.

The key flawed assumption underlying the Nagourney and Martin’s analysis is that Trump would continue to face “a crowded field.” Candidates faring poorly in early primaries and caucuses have dropped out in past campaigns in both parties. Typically, some aspirants who poll badly and struggle to raise funds in the year before voting begins do not even make it to the Iowa caucuses.

In the 2012 Republican race that was the fate of Tim Pawlenty and Herman Cain. In 2008 Tommy Thompson, Sam Brownback, Tom Tancredo and Jim Gilmore all withdrew from the GOP race before a vote was cast. Evan Bayh and Tom Vilsack withdrew from the 2008 Democratic presidential race many months before the Iowa caucuses. In the 2016 cycle, this ”winnowing” process has already begun with the collapse of former Texas governor Rick Perry’s campaign on Sept. 11. Other struggling candidates will probably call it quits before the end of  2015.

History also suggest that the early contests in Iowa, New Hampshire, South Carolina and Nevada — which combined have just over 5 percent of the total delegates — will eliminate most of the remaining candidates. By the time of the March 1 Super Tuesday contests – which account for just under a quarter of the delegates — the field should have thinned considerably. All of these early contests are conducted under proportional allocation rules that divide up delegates among candidates in rough proportion to their vote share, or at least winner-take-all at the district level, allowing for multiple candidates to win delegates in a state. Several more contests are scheduled in the days following Super Tuesday.

Statewide winner-take-all contests, which Nagourney and Martin suggest Trump could win with one-third of the vote, are not permitted until March 15. By that time, if Trump is still a strong contender, Republicans resistant to him will have had plenty of time to rally behind an alternative choice. If Trump wins, it will be because he wins over more Republican voters than he is currently attracting.

The Times reporters and their GOP informants are seasoned observers. They have witnessed and participated in prior campaigns in both parties in which many candidates folded their tents after the early contests. Why then do they assume 2016 will be an exception? They cite super PACs that allow candidates to raise vast sums from a handful of backers, allowing them to prolong their campaigns, despite early setbacks.

Yet there is reason to doubt that super PACs have changed things all that radically. Perry’s withdrawal from the race despite having several millions left in his super PAC coffers is a reminder that candidates still need “hard money” to provide for campaign expenses. A candidate who is doing very badly will have a hard time raising such funds.

Beyond that, the focus on super PACs overstates the importance of money in previous contests. It is not only a shortage of funds that has sunk previous campaigns.  Candidates who do badly in the early primaries and caucuses receive much less media coverage. They start to seem less viable to voters. Much as “better than expected” showings in early contests boost some candidates, others who underperform suffer going forward.

This is a vicious cycle for candidates; failing to do well in early contests makes it hard to get coverage or to raise money, which typically results in further poor showings. For almost all candidates this is a death spiral. Losing – especially losing badly — begets losing. Political scientist Larry Bartels wrote about this a generation ago, and it is still the case.

Occasionally a candidate can retain some support despite repeated poor performances because he appeals to a niche within the electorate. Ron Paul and Jesse Jackson are examples. Such “message” candidates are very much the exception however, and this year’s crop of candidates bears little resemblance to them.

Beyond this general dynamic, the current field of candidates face state specific challenges. Wisconsin Gov. Scott Walker, for example, is focusing his faltering campaign on Iowa, where he once led in the polls. As the chief executive of a neighboring state, Walker cannot expect to do well elsewhere if he doesn’t succeed in Iowa. The Hawkeye state is also crucial for the two candidates who won there in the past, former Arkansas governor Mike Huckabee and former Pennsylvania senator Rick Santorum.

Ohio Gov. John Kasich is banking on a breakthrough in New Hampshire, as are New Jersey Gov. Chris Christie, Kentucky Sen. Rand Paul and former New York governor George Pataki. It is hard to see a candidate staying in the race after losing his home state, a prospect South Carolina Sen. Lindsey Graham faces early next year.

Understanding the properties of the nominating system is an important challenge for candidates, reporters and citizens who want to participate effectively in the process or seek to improve it.  The weeding out of candidates via the iterated nature of the nomination process is a very basic aspect of the system. The system has evolved, and no doubt will continue to, but the burden of proof should be on those asserting that things have changed fundamentally.