October 8, 2015 7:11 AM EDT

Three years ago at the Republican convention in Tampa, a group of party elders changed the GOP rule book. Only candidates who won a majority of the delegates in eight states should be eligible to be nominated in 2016, they decided. It seemed like a good idea at the time.

That rule has since become just one more reason the presidential nomination fight could drag out into the spring, perhaps even all the way to the GOP convention in Cleveland. A rare combination of players, politics and party rules has officials increasingly worried about a protracted fight that could benefit Democrats.

“This is totally uncharted waters for any national political party,” warns Richard Hohlt, a Washington lobbyist who is one of many GOP insiders sounding the alarm. Inside headquarters, senior party officials acknowledge that the coming fight will be “intense.”

The concern is a reversal for the GOP, which is traditionally the more ordered of the two parties, following long-established rules that are largely invisible to voters. Those rules, party elders have discovered, can cut both ways. Here’s why.

Too many rivals: The main complication is the sheer number of candidates. At 15, the Republican field is almost double the next largest in history. This has complicated polling and debates, but the bigger impact could come this spring. Many candidates have pinned their hopes on winning over opponents’ voters once those opponents drop out. That makes the race a waiting game.

Too much Democracy: In 2016, more GOP delegates than ever before will be awarded on the basis of the popular vote in each state, as opposed to the GOP’s old (and less democratic) practice of awarding delegates on a winner-take-all basis. This virtually guarantees multiple winners through the first six weeks of voting and could deprive the party of an early front runner who could quickly wrap up the nomination.

Spring break! Just when a front runner might have emerged, the GOP calendar includes a spring break from mid-March to mid-April. Fewer than 8% of the delegates will be awarded over the course of that month, possibly sapping momentum from the leader. Less-well-funded challengers will have time to regroup in the hopes of pulling off surprise upsets in late April and May.

Too many sugar daddies: For decades, candidates who lost early state contests were forced out when their money dried up. But the new wealthy donor class writing multimillion-dollar checks to candidates’ super PACs could help early losers by providing the backup of costly campaign-ad buys down the stretch. A candidate like Texas Senator Ted Cruz could keep his crusade alive for weeks or even months longer than under the old system.

Cherry-picking: Candidates are revising their strategies to prepare for a race in which every delegate matters. Cruz has deployed staffers to Guam and the U.S. Virgin Islands in hopes of picking up the delegates needed to mount a challenge at the convention. Meanwhile, Jeb Bush’s campaign is working to lock down supporters well beyond the March 1 states in preparation for the long slog.

Officially, party bosses say there is no need to panic. The party chairman, Reince Priebus, predicts there will be a nominee by early spring. He’s counting on the political laws of gravity to force underperforming candidates from the race in a timely fashion. (A lack of money and momentum has already ushered out Wisconsin’s Scott Walker and Texas’ Rick Perry.) But Priebus is nonetheless concerned enough about a deadlocked race that he has quietly reached out to a handful of GOP veterans to help him think through the problem.

They will consider such thorny issues as what to do about the 2012 rule requiring nominees to have won eight states. That rule can always be rewritten at the convention, say party bigwigs, if it will help speed selection of a nominee. But last-minute rule changes by party insiders would likely be met with fury from a rank and file not accustomed to the tyranny of the smoke-filled room. The fear in Washington is that the forces that have propelled Donald Trump and Ben Carson in the polls and exiled Speaker of the House John Boehner from Congress will unify to challenge other convention rules as the event approaches.

“We’re seeing the pitchforks ascendant in Washington,” one party graybeard observes. “Just wait until they realize what trouble they can cause in Cleveland.”

This appears in the October 19, 2015 issue of TIME.

Contact us at editors@time.com.

Read More From TIME

Related Stories

EDIT POST