RFK Jr. and MTG are using the same dismissive term for major-party differences. I took at look at this phenomenon at New York:

Partisan polarization has been steadily growing in the U.S. since roughly the 1960s. Ironically, during this time, the complaint that the two parties are actually too alike has become increasingly prevalent. For years, right-wing Republicans have called people in the GOP who don’t share their exact degree of ideological extremism RINOs, or “Republicans in name only,” suggesting they’re basically Democrats. Left-wing Democrats occasionally echo these epithets by calling (relative) moderates “DINOs,” “ConservaDems,” or — back when maximum resistance to George W. Bush was de rigueur — “Vichy Democrats.”

Today the term “Uniparty” has come to denote the idea that Democrats and Republicans are actually working for the same evil Establishment enterprise, their loudly proclaimed differences being a mere sham. This contention was the culmination of a five-page letter Marjorie Taylor Greene recently sent her Republican colleagues calling for House Speaker Mike Johnson’s removal, unless he changes his ways instantly. She wrote:

“With so much at stake for our future and the future of our children, I will not tolerate this type of ‘leadership.’ This has been a complete and total surrender to, if not complete and total lockstep with, the Democrats’ agenda that has angered our Republican base so much and given them very little reason to vote for a Republican House majority …

“If these actions by the leaders of our conference continue, then we are not a Republican party – we are a Uniparty that is hell-bent on remaining on the path of self-inflicted destruction.”

Independent presidential candidate Robert F. Kennedy Jr. also leaned heavily into the Uniparty idea in his recent speech introducing running-mate Nicole Shanahan:

“Our independent run for the presidency is finally going to bring down the Democrat and Republican duopoly that gave us ruinous debt, chronic disease, endless wars, lockdowns, mandates, agency capture, and censorship. This is the same Trump/Biden Uniparty that has captured and appropriated our democracy and turned it over to Blackrock, State Street, Vanguard, and their other corporate donors. Nicole Shanahan will help me rally support for our revolution against Uniparty rule from both ends of the traditional Right vs. Left political spectrum.”

The Uniparty claim is ridiculous, of course, as FiveThirtyEight’s Geoffrey Skelley demonstrates:

“[O]ur current political moment is arguably farther away from having anything resembling a uniparty than at any other time in modern U.S. history. Based on their voting records, Democratic and Republican members of Congress have become increasingly polarized, and both the more moderate and more conservative wings of the congressional GOP have moved to the right at similar rates. Meanwhile, polling suggests that Americans now are more likely to view the parties as distinct from one another than in the past, an indication that the public broadly doesn’t see a uniparty in Washington. Although there are areas where the parties are less divided, the broader uniparty claim is at odds with our highly polarized and divided political era.”

Kennedy’s subscription to the Uniparty notion is understandable on two points. The first is that his candidacy is vastly more likely to tilt the 2024 presidential campaign in the direction of one of the two major-party candidates (likely Donald Trump, according to most of the polling) than to actually succeed in winning the presidency. Maintaining that it really doesn’t matter whether it’s Biden or Trump running the country is essential to maintaining RFK’s appeal as November approaches and the futility of his bid becomes clearer. Second, Kennedy’s pervasive conspiracy-theory approach to contemporary life lends itself to the argument that the apparent gulf between the two major parties is a ruse disguising a sinister common purpose.

MTG’s Uniparty contention also reflects dual motives. In part she is simply echoing Trump’s weird but useful contention that he’s an “outsider” battling a Deep-State Establishment that secretly controls both parties, which is pretty rich since he dominates the GOP like Genghis Khan dominated the Golden Horde. But there is a marginally more legitimate sense in which key elements of the two parties really are in line with each other on isolated issues that happen to obsess Greene, such as aid to Ukraine. If you are a hammer, as the saying goes, everything looks like a nail.

The same is true of other implicit Uniparty claims, particularly those made by progressive pro-Palestinian protesters who adamantly argue that the need to smite “Genocide Joe” Biden for his pro-Israel policies outweighs all the reasons it might be a bad idea to help Trump return to the White House (including the fact that Trump is palpably indifferent to Palestinian suffering). If the two parties do not appear to differ on your overriding issue, then the fundamental reality of polarization can fade into irrelevance.

So we’re likely to hear more Uniparty talk even as Democrats and Republicans head toward another highly fractious election with very high stakes attributable to their differences.