The Republicans began as a party of rights but ended up being a party of economic opportunity — precisely the opposite 20th-century passage of the Democrats — and so now the wealth gap is a peculiarly perplexing challenge for them. In the waning years of the Great Society, Ronald Reagan began questioning the Democrats’ prescriptions for economic opportunity, an effort that through four presidential campaigns (1968, 1976, 1980 and 1984) he developed into a new ethos with its own catch-phrase (“opportunity society”).

So deep did that catch-phrase penetrate that, nearly a year before the 2012 election, former Gov. Mitt Romney of Massachusetts, who would eventually win the GOP presidential nomination, framed his campaign as a choice between the “opportunity society” of the Republicans and the “entitlement society” of the Democrats.

Democrats for a few tantalizing weeks may have luxuriated in portraying Mr. Romney, who until Friday morning considered a 2016 presidential campaign, as a Harvey Comics figure (Richie Rich redux) but he actually has been supporting an increase in the minimum wage for eight months. He did so with the pointed aside that, as he put it, “I part company with many of the conservatives in my party on the issue.”

Now, many of those same conservatives are struggling to find ways to address the wealth gap. The new Republicans — and not only those affiliated with the Tea Party insurgents — are loathe to associate themselves with figures of great wealth like Mr. Romney, whose possible appearance in the 2016 race was for them a disturbing symbol of the resilience of the East Coast establishment that GOP rebels have remonstrated against since the Barry Goldwater campaign of 1964.