Chronic campaigner Mitt Romney, who evidently hopes that a deadlocked Republican convention would turn to him, has inadvertently shot a flare across the psychic landscape of American politics. (Needless to say, he's unlikely to have the self-awareness to grasp any of this, but it's still a kind of intellectual public service, wholly leaving aside the question of how it ends up affecting the election.)
Political debate is often conducted in terms of ideas, and conceptualized in terms of economic interests, and both clearly matter a lot. But also vitally important are feelings about hierarchy and subordination, which can involve both (a) tensions between rival claimants to elite status, and (b) popular resentment of elites' claims that they are entitled to lead and guide the rest. How all this is conceptualized, however, can be startlingly heterogeneous.
Let's start with Romney's broadside against Trump, which I (like many others) found wildly hypocritical. Consider Romney's own willingness in 2012 to dip his well-pedicured toe into the waters of racism, anti-immigrant sentiment, hypocritical flip-flopping out of political opportunism (e.g., Romneycare / Obamacare), and dishonest under-specification of his fiscal plans (e.g., while Trump of course doesn't explain how he'd pay for his tax cuts - he can't - Romney similarly couldn't explain how he'd cut rates so steeply without either losing revenue or raising middle and lower-echelon taxes). And it's not just Romney in 2012; Cruz and Rubio are also both guilty on all these counts; at most there's a modest manner of degree as between them and Trump, and even that is debatable in some of the relevant dimensions.
But I'll give Romney credit for one thing - despite the underlying calculation and evident hypocrisy, it seems clear that Trump has genuinely enraged him. For this I see two main causes.
The first is that he finds Trump simply too vulgar to be an acceptable member of the leadership class. As others have noted, we're seeing a replay of Caddyshack, with Romney having taken Jeb's place in the Ted Knight role, and Trump still playing Rodney Dangerfield. You can accept an endorsement from such a person, as Romney did in 2012, and perhaps you can even give him gracious verbal props as part of the arrangement, but to Romney this does not contradict taking the stance he does now when one of Those People gets so out of line and above himself.
Second, Romney is furious because Trump has been unacceptably rude towards other members of the Republican leadership class. It's okay to defame your political enemies, as well as, say, members of the "47%," but it's not okay to be so rude as Trump has been to the likes of McCain, Jeb, and Rubio. These people are supposed to be treated respectfully as a personal matter, even if you take a shiv to them politically. (Or at least, you need to subcontract the thuggery, a la the George W. Bush campaign's slanders against McCain in the 2000 South Carolina primary.)
So we have Romney sincerely and passionately defending one of the few things (beyond himself) he actually cares about - the right of the Republican leadership class to keep out vulgar parvenus and to be treated respectfully.
This brings us to the other side of the coin - the anger that Romney's stance has triggered among Trump voters who espy a "patronizing directive from an elite figure who thoroughly misunderstands their feelings of alienation from the political system."
So we have social battles among rival elites, plus popular anger over what is viewed as an elitist asserting his prerogatives.
Two more general comments. First, it's noteworthy how pervasive this type of thing is in American politics. For example, a sentiment underlying the Sanders campaign is that the economic elite - the top 0.1 percent - has gotten out of control and needs to be reined in. But one reason for Sanders' apparently limited political appeal is that not everyone who is angry about perceived or actual subordination is coding the problem this way. Obviously, within the Democratic race, there's been the question over relative focus on plutocracy versus, say, issues of racial hierarchy and subordination. And, equally obviously, those on the right who are angry about elites telling them what to do often direct their anger at targets other than plutocracy. For decades - think of George H.W. Bush insisting that he liked to gnaw on pork rinds - we've had Republicans tapping mass resentment of elites defined quite differently - intellectuals or Ivy Leaguers or civil servants, for example. And this evidently has authentic roots of a kind. Richard Nixon, the dark genius of American politics during his long (1946-1974) career, was able to put his finger on it in part because he himself had felt it when dealing with those he thought of as members of the Ivy League "Eastern Establishment."
Second point, already illustrated by the above paragraph: there's remarkable heterogeneity around how elites are defined, whether they're (a) battling with each other or (b) being targeted for popular resentment. Consider the rage of many business and financial industry types over the Obama Administration's rather mild (I thought) criticism of them after the 2008 financial meltdown. And, to be fair, consider as well how people like me think about the problem of plutocracy in current U.S. politics and society. An important subtext here, and source of the anger and passion on both sides, is the rivalry between economic/business and intellectual/academic self-styled elites, who invoke different ranking systems for determining who deserves authority and deference. Now, I would say that the other group's resentment is a bit farcical, given how much more power (and everything else) they clearly have than anyone else, most definitely including my own group. But then again, I'm saying this from the inside of the dispute, not from a lofty perspective above it.