There's two ways to look at this, but before we do that, let's look at the pertinent portion of Rule 40(b):
(b) Each candidate for nomination for President of the United States and Vice President of the United States shall demonstrate the support of a majority of the delegates from each of eight (8) or more States, severally, prior to the presentation of the name of that candidate for nomination.
Trump and Cruz have both already done this. Okay so far. But remember that the conventional wisdom is defining "shall demonstrate the support of a majority of delegates" as having won a majority of delegates in the primary/caucus elections. But that isn't the entirety of that definition:
Notwithstanding any other provisions of these rules or any rule of the House of Representatives, to demonstrate the support required of this paragraph a certificate evidencing the affirmative written support of the required number of permanently seated delegates from each of the eight (8) or more States shall have been submitted to the secretary of the convention not later than one (1) hour prior to the placing of the names of candidates for nomination pursuant to this rule and the established order of business. [emphasis added]
In other words, it isn't enough to have won a majority of delegates in eight or more States; to be eligible for nomination, a candidate has to prove in writing that those delegates actually and actively support him. Which, in any normal cycle, is a pro forma detail, the front-runner having become the presumptive nominee months earlier and the convention being a general election-focused coronation.
But, of course, this cycle is the antithesis of normal, with a liberal authoritarian interloper having duped and conned his way to the delegate lead and many of his pledged delegates being opposed to him but coerced by the rules to vote for him on the first convention ballot. Which would, when you stop and think about it, constitute the party rules working in Trump's favor, not unlike the fact that he's won 36% of the primary/caucus vote to date and garnered 45% of the delegates. And you'll notice that he isn't bitching and moaning and whining and throwing Twitter tantrums and fomenting death threats against GOP officials from his followers about that.
But as Rule 40(b) reads, maybe the pro-Cruz Trump-pledged delegates aren't hostages after all. And maybe they could deny Trump's name from ever being placed in nomination at all, on any ballot, and Senator Cruz could be nominated by acclamation.
You have to admit, the poetic justice would be orgasmic.
The problem with this glorious scenario is that it pretty much completely negates the primaries and causcuses. Nobody is more #NeverTrump than I am, but the GOP did hold a primary campaign, with elections in each State according to each State's various and sundry rules. Some went the way I wanted to see them go, a lot of them did not. But they turned out the way they turned out, and the remaining ones will unfold accordingly. Clearly, as we are seeing, those results are not the be-all and end-all; organization and ground game and delegate-wrangling is part of the nomination process as well. But the primaries and caucuses should mean something. Otherwise, why bother holding them in the first place? Just announce that the nomination will be determined at the convention and that's that, no primaries, no caucuses, nothing other than smokeless back rooms.
That would have provoked the tiresomely predictable "populist" flash-rage reaction; but it would have done so more than a year ago. If the rules and playing field are established in the beginning and some people don't like them, fine, they can boycott or piss and moan to their heart's content; that's one thing. But to establish the rules and playing field and then change them after the fact if the results aren't to the establisher's liking, especially in a political contest, is, well, politically insane.
Let's cast this in the current context: Trump threw a shit-fit over getting shut out in Colorado last weekend, hurling baseless, vitriolic charges of having been "cheated" and the proceedings having been "fixed" when the incontrovertible FACT is that the Colorado GOP established and published their nomination rules over a year ago, Trump could have hired competent people to get him up to speed on them, done his homework, and prepared to recruit and get his delegate slates installed to the maximum extent possible - all just like Ted Cruz's campaign did - but he didn't. He failed. He didn't think he needed to, or wasn't even aware that it was a necessary part of running for the GOP presidential nomination. HE SCREWED UP, and then blamed the party for his self-defeating blunder instead of admitting and owning it. But if, after winning (narrowly) the most nominating contests and delegates, Trump wasn't even allowed on the first ballot in Cleveland based upon what would immediately, and not inaccurately given the very fact of fifty State nominating contests having been held, be denounced as a technicality, all the resulting rage and violence - well, not the violence, of which there would be a-plenty, but the anger, anyway - would be awfully difficult to call unjustified.
And that is why I don't believe Rule 40(b) will be read this way, for the same reason that the "establishment" parachuting in a "white knight savior" won't be attempted. In terms of public perception it would be a reprise of the "Corrupt Bargain" of 1824, a short-term maneuver on the part of the Whigs that ignited a generation of "populism" that began America on the downward spiral from the republic it originally was to "Jacksonian democracy" to the mobbish socialist oligarchy it has become today. We're already beset and besieged by enough of that poisonous nonsense as it is; genuinely screwing Trump would entrench it for years to come.
Folly and insanity and personality cults have to be allowed to run their course and make their grievous mistakes so that the cautionary lesson of why "populism" is dangerous and anti-constitutional may be restored in the nation's political immune system.
As I have been saying, so I reiterate here: The Cleveland convention should and will be a battle of first ballot (Trump) versus subsequent ballots (Cruz). If Trump can get to 1,237 on the first go-round, he's the nominee; if he doesn't, he won't be. Let it be left at that, and not lend the tiniest scintilla of truth to the Trumpertantrums to come.