Every four years, journalists fantasize about the prospect of a convention in which the evening begins without knowing when or how it will end. In spite of his favorable odds in Illinois Tuesday, Mitt Romney's failure so far to effectively end the contest before the vernal equinox has triggered hopes that, for decades, have ended as cruelly as the Kansas City Royals' hopes for a post-season berth.

Well, I bring you good tidings. If Romney has not secured the nomination by the time the delegates convene in Tampa, Fla., at the end of August, the prospects for a genuine floor fight are greater than you might imagine. The reason is that delegates who are bound or pledged to a candidate are only obligated to follow his wishes when it comes to voting for a nominee. And in most contentious conventions, it is a fight over the rules that has effectively determined the nominee.

Let's have a look at the last three conventions where the outcome was in any sort of doubt:



1972 Democratic Convention: George McGovern won the California Democratic primary by a 44-39 ratio over former Vice President Hubert Humphrey. But under the state's winner-take-all election, he won all 271 delegates. At the convention, the credentials committee invalidated that system and divided the delegates proportionately, a fatal threat to McGovern's hopes in the first round of voting. After a passionate floor debate, the convention restored McGovern's delegates and he clinched the nomination.

1976 Republican Convention: Ronald Reagan tried to thwart President Gerald Ford's delegate lead by breaking with tradition and announcing his choice for vice president before the nominee was determined: liberal Pennsylvania Sen. Richard Schweiker. His campaign then proposed a rule—16(c), if you're keeping score—requiring all candidates to do the same. The hope was that whoever Ford chose would alienate enough delegates to force a second ballot and shake loose some of the president's supporters. By a narrow vote of 1,180-1,068, the rule was defeated and Ford secured the nomination.

Story continues

1980 Democratic Convention: Ted Kennedy's backers, arguing that he had prevailed in most of the later primaries, sought to free all delegates of their pledges and turn them into free agents so they could vote based on the how the political terrain now appeared. In response, President Jimmy Carter's campaign pushed through the unfortunately deemed "bind and yank" rule, which permitted the Carter forces to replace any wavering delegate with one loyal to the president. That put an end to the nomination contest.

If Romney comes to the convention several dozen delegates shy, and if he has suffered setbacks in late primaries, these kinds of challenges may well lie at the heart of the anti-Romney strategy. Here it is critical to remember that delegates who may be bound to vote for Romney on the first ballot do not have to stand with him on anything else. Specifically in states like Alabama, Mississippi and other conservative bastions, it is more than likely that there will be delegates bound to Romney who would not support him if they had a choice.

Let's look at a couple of plausible scenarios:

Scenario One: Florida and Arizona's delegates become free agents

Florida and Arizona were penalized half their delegates for jumping to the front of the primary calendar. But both were winner-take-all states, even though Republican rules clearly stated that early primaries had to allocate delegates proportionately. If the anti-Romney forces brought a challenge to the floor, there is nothing that would require anyone—bound, pledged or "morally bound"—to vote with the Romney forces. A loss here would mean that at least 30 of the 79 total delegates from Florida and Arizona could vanish from Romney's column.

Scenario Two: All candidates become free agents

Suppose the challenge to Romney is broader, and that, like the Kennedy forces did in 1980, the opposition offers a rule to free all the delegates from their commitments on the ground that the primaries have demonstrated Romney's weakness. Here, we could see a number of delegates bound to Romney vote to liberate themselves from the obligation to vote for him. (Again, we should note that delegates bound to vote for Romney as the nominee don't have to side with him on other votes that stand to determine his fate.) Sure, most delegates would probably stand by the former governor on grounds of loyalty, fairness or fear of reprisals. But if Romney has not garnered a large enough share of delegates by convention time, it would not take many defections to make every delegate a free agent, and thus turn the whole convention upside down.

Scenario Three: Wild card

Imagine a platform plank that repudiated health care individual mandates "at the national or state level," a clear stick in Romney's eye (and, I suspect, a sentiment the majority of delegates would embrace). Or imagine a proposal that the candidates participate in a debate in front of the convention before the balloting begins. Or suppose Romney prevails, but his foes contest his vice-presidential selection. There are countless other ways for a convention to turn contentious.

These possibilities underscore the reason why an exclusive focus on the delegate count is so misleading, and why the effort to figure out which delegates are or are not legally committed to a candidate is only part of the picture. Yes, it's useful to remember that Colorado delegates are unbound, that the Ohio delegates are only "morally bound," and that the "automatic delegates" from each state are free agents. But the real prospect for upheaval is that no delegate is bound to follow the preferences of his or her candidate on any platform, credential or rules debate. And it is no coincidence that in '72, '76 and '80, the survivor of such convention tension lost in November.

Jeff Greenfield is co-host of PBS' "Need to Know" and a Yahoo! News columnist. Follow him on Twitter: @greenfield64.

More popular Yahoo! News stories:

• Porn titans not worried about Rick Santorum banning their business

• In Ronald Reagan's hometown, Rick Santorum compares Mitt Romney to Gerald Ford

• Romney's ties to China surveillance firm whacked by Obama campaign

Want more of our best political stories? Visit The Ticket or connect with us on Facebook, follow us on Twitter, or add us on Tumblr. Handy with a camera? Join our Election 2012 Flickr group to submit your photos