Cleveland could be a riot yet. Photo: Spencer Platt/Getty Images

After several weeks of sunny weather for Donald Trump’s presidential campaign this spring, marked by the rapid surrender of his intra-party opponents and strong general-election poll numbers against Hillary Clinton, Republicans are again in semi-panic over his behavior. The backlash to Trump’s racially tinged comments about Judge Gonzalo Curiel, and the putative nominee’s apparent inability to back away from them, has the senior leaders of the party unable to defend him. South Carolina senator and former presidential candidate Lindsey Graham, quite recently the quintessential Trump disparager who was reconciling himself to the mogul’s candidacy, is now sounding a new alarm and urging fellow Republicans to withdraw their endorsements: “This is the most un-American thing from a politician since Joe McCarthy,” he told the Times. “If anybody was looking for an off-ramp, this is probably it. There’ll come a time when the love of country will trump hatred of Hillary.” Meanwhile, Mitch McConnell has offered the candidate a terse directive: “Get on message.”

So is there actually some mechanism whereby Republicans could dump Trump if the panic spreads or the “putative nominee” freaks out and starts blaming his troubles on a conspiracy between ISIS and the Cisco Kid?

Well, yes, there is a nuclear option — but it still has to be considered very unlikely. Approximately one-third of the delegations to the Republican National Convention will be bound to primary or caucus winners by state election laws. For the rest of them, however, the “binding” is by national party rules, and ultimately the rules of every Republican convention are made and can be unmade by the convention itself. So, in theory, convention delegates could vote to unbind themselves (or at least those not bound by state election laws) before the first presidential ballot and throw the nomination open again. If you recall that a significant number of “Trump delegates” are not personally loyal to the wiggy dude to begin with, you could see how a revolt could gain traction under very precise — and unlikely — circumstances.

There are two internal GOP conditions that would need to be present before the nuclear option could ever come into play. The first would be a widespread abandonment of Trump by the very party opinion-leaders who have been climbing aboard his bandwagon in the last few weeks — a mass exodus on the “off-ramp” Graham is talking about. The second and more important development would be a radical change in the rank-and-file sentiment — which was strongly evident long before Trump appeared to have nailed down the nomination — opposing any kind of “coup” against the primary results.

Regardless of what Lindsey Graham and other fair-weather friends of Donald Trump think, neither of these things is going to happen unless there is first a sudden, sickening downward lurch in Trump’s general-election poll numbers. I doubt anything other than 20 points or so — and with it a renewed fear of a down-ballot disaster for the GOP — would get the dump-Trump bandwagon rolling. At that point, all hell could break loose, and Cleveland could be wild and crazy fun after all.