Donald Trump in Phoenix on Saturday. (Ross D. Franklin/Associated Press)
Opinion writer

When it comes to the chaotic, flailing, floundering Trump campaign, many senior Republicans are in a state of panic. Will this become a state of revolt?

“If the next few weeks are anything like the last two,” a senior GOP official told me, “anything could happen at the convention.” Donald Trump’s response to the Orlando attack — encouraging religious bigotry and implying that President Obama might be a secret jihadist — confirmed the worst Republican fear: that Trump will remain Trump.

With this recognition has come the realization that Trump has wasted the seven weeks since becoming the presumptive nominee — a period in which Democrats were divided and vulnerable. How did he fill the vacant air? He raised the possibility that Ted Cruz’s father might be implicated in the assassination of JFK; that Hillary Clinton might have been involved in the death of Vince Foster; that a federal judge, presiding over a case against Trump University, should be disqualified by his ethnicity; and that American soldiers in Iraq were living large off larceny.

By the end of this string of statements, one of Trump’s strongest congressional proxies, Rep. Duncan Hunter (Calif.), was reduced to arguing: “I think what he says and what he’ll do are two different things.” Republicans, in essence, should be reassured by their nominee’s duplicity.

House Speaker Paul D. Ryan (Wis.) and Senate Majority Leader Mitch McConnell (Ky.) have been willing to criticize Trump but not to un-endorse him. Practically, this means that nothing — nothing — Trump says could forfeit their support. The presumptive nominee has already raised the prospect that his opponent is a murderer and that the president is a traitor. Not, evidently, sufficient provocations. Ryan and McConnell have decided that in order to remain leaders they must avoid providing leadership.

In his speech after the Orlando mass shooting, Republican presidential candidate Donald Trump said that Muslims "have to cooperate with law enforcement and turn in the people who they know are bad." (Reuters)

But what might change things in the GOP is the political disaster that now appears in the offing. Beneath Trump’s historically low approval ratings — 29 percent in a recent Post/ABC News survey — is an even more disturbing development. After securing the nomination, Trump’s support among Republicans rose, in many polls, to the mid-80s — not spectacularly good but an indication that the GOP was rallying. In recent polls, Trump’s Republican support has dropped to between 70 and 80 percent. Along this trend, a decisive Democratic victory might sweep away the House and Senate. If Republican politicians begin to see this dynamic in their own polling, many will suddenly rediscover their consciences and abandon Trump.

Trump’s whole campaign now consists of a pathetic irony. He ran attacking the Republican “establishment” at every turn. Now, since he has neglected to construct his own national campaign, he is completely dependent on the “establishment” to provide his political ground game. First he vilifies the GOP, then he complains that it lacks enthusiasm for his cause.

Republican convention delegates are sophisticated enough to see what is happening. The Trump campaign claims to be lean; in most of the country, including the battleground states, it is nonexistent. Trump offers his leadership as the solution to every problem yet presides over a campaign organization that is a squabbling, paralyzed amateur hour. Delegates know that even if Trump can boost his poll numbers, he cannot magically create a viable, national campaign structure.

If a revolt emerges, it will happen first in the GOP convention rules committee — which meets a week before the convention and is stacked with officials more loyal to the party than to Trump. The simplest move would be to require a supermajority to select a nominee — an approach taken by some Republican state conventions in order to avoid the choice of badly wounded candidates. The goal should be a truly open convention, which does not choose anyone Trump has already beaten.

Trump’s response to his swift political decline has been to continue his primary campaign — accusing Jeb Bush of suddenly recovering the energy to plot against him. This comfortable attack makes sense, given that Trump has succeeded by appealing to a niche market that is impressed by his instinctive nativism and Kardashian-like celebrity. So far, the niche candidate has failed to make the transition to a national message. And given the adoration and enthusiasm of his crowds (one recently chanting: “Build a wall and kill them all!”), Trump has no emotional motivation to change direction, whatever the polls might say.

A delegate revolt would be a messy spectacle, with little hope of succeeding unless Ryan and Reince Priebus eventually break with Trump. But it is now the only option consistent with Republican interests and honor.

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Republican presidential candidate Donald Trump's campaign raised just $3.1 million in May, while Democratic rival Hillary Clinton brought in $27 million. Here's a breakdown of the two campaigns' finances. (Jenny Starrs/The Washington Post)