Democratic Sens. Kyrsten Sinema (Ariz.) and Joe Manchin III (W.Va.) are mentioned in the same sentence so frequently that there’s a raging battle on Twitter over whether Manchinema or Sinemanchin is the correct portmanteau. But despite the obvious similarities between the two most conservative members of the Democrats’ Senate caucus — notably their opposition to the size of President Biden’s major domestic-spending bill, as originally introduced, and willingness to buck their party’s leadership — Manchin and Sinema represent very distinct political visions.

A reputation for independence, by itself, can have some electoral allure. But Manchin’s departure from the Democratic mainstream — however much it infuriates progressives — offers something of a road map for appealing to less-educated and rural voters, especially White ones, whom the party badly needs to win if it wants to hold future Senate majorities. Sinema, by contrast, offers little beyond vague fiscal conservatism. She chooses politically perverse topics on which to make a stand, blocking some of Biden’s most popular ideas, and offers nothing for the party to build on.

To an extent they sometimes fail to appreciate, Democrats are incredibly lucky to have someone as open to their ideas as Manchin representing such a deep-red state. Biden, after all, attracted a mere 29.7 percent of the presidential vote in West Virginia in 2020, and the Democratic challenger to the state’s other senator, Shelley Moore Capito (R), got 27 percent. On the face of it, Democrats would appear to have something to learn from Manchin, who has served in the Senate for more than a decade, about selling the party’s brand in inhospitable political territory.

The Sinema story is very different. Her 2018 win seemed very impressive at the time, given Democrats’ relatively poor recent track record in Arizona. But Mark Kelly, a much more conventional Democrat, beat literally the same opponent (Martha McSally) two years later, and won by exactly the same margin as Sinema despite an overall national political climate that was much less favorable to Democrats than it had been in 2018.

Perhaps people just love astronauts (Kelly made four trips into space before following three predecessors into Congress). But while it’s generally true that moderates have better electoral performance relative to progressives, Sinema’s choices of which hills to die on are not especially politically adept. She attracted attention early in Biden’s term with a showy thumbs-down for a minimum-wage increase, for instance, even though minimum-wage referendums routinely win even in very red states such as Missouri (to say nothing of Arizona itself, where a minimum-wage initiative passed 58 to 42 percent back in 2016).

The progressive data and analytics firm Blue Rose Research recently set out to rigorously assess the popularity of a wide range of progressive policy proposals. Blue Rose wanted to move beyond traditional issue polling (where almost anything tends to look popular because respondents like to answer “yes” to pollsters) by asking questions that feature explicit partisan framing and counterarguments. In this environment, lots of cherished Biden initiatives such as the expanded child tax credit fare poorly. But other progressive ideas like adding dental and vision benefits to Medicare do well. The single best-scoring item on the agenda, as measured by Blue Rose, is letting the federal government bargain down the price of prescription drugs. A recent Kaiser Family Foundation poll found similarly deep support for that policy: Even when voters heard the argument that price negotiation could hamper drug innovation, a large majority — including 71 percent of Republicans — still liked it.

Like the minimum wage, this is an issue that Democrats can take into tough races and try to win on. And if the national electorate primarily associated the Democratic Party with ideas like lower prescription drug costs, rather than lifestyle liberalism and avant-garde cultural politics, it wouldn’t face such punishing disadvantages in the Senate and the electoral college. But Sinema opposes the idea — and by doing so, she may cost Biden his single best opportunity not only to make health care more affordable for many Americans but also to do something voters will like, and remember. (The money saved through price negotiation would also help pay for other programs in the bill.)

More broadly, Sinema is also against increases in the top income tax rate or the corporate tax rate. This is a nearly unprecedented stance for a Democrat, especially considering that Sinema voted against President Donald Trump’s tax cut bill when it passed in 2017. In a telling move the following year, though, she not only voted to extend the Tax Cut and Jobs Act’s temporary provisions but explained that “my big complaint when the tax bill passed last November was that it didn’t provide permanency for small businesses who use pass-through taxes to run their businesses and it didn’t provide permanency for middle-class families.”

These provisions are, indeed, popular with a small number of high-income business owners but low taxes on the rich are one of the GOP’s least-popular policy commitments, with the Pew Research Center consistently finding that the public’s top two complaints about the tax status quo are that corporations and the wealthy pay too little. During Trump’s first two years in office, a big business tax cut was his main policy achievement, and it was followed by massive Democratic midterm wins — yet this is the part of the Trump legacy that Sinema wants to entrench?

By contrast, Manchin, in his summer letter to Senate Majority Leader Charles E. Schumer (D-N.Y.) expressing doubts about Democrats’ expansive budget reconciliation package, clearly embraced higher taxes on the rich. He called for increasing the corporate tax rate and the top individual income tax rate, imposing a higher levy on capital gains, and closing the carried interest loophole.

His difference with party leaders is that he wants to limit new spending to $1.5 trillion and dedicate any additional revenue to deficit reduction. This is at odds with the fiscal policy views of the Biden White House (and is frankly a bit odd on the merits, given the current low interest rates), but you only need to go back to President Barack Obama to find a time when Manchin’s view was the dominant current of Democratic thought. The public, meanwhile, at least professes to be concerned about the deficit — 49 percent of Americans tell Gallup that they worry about it “a great deal” and 28 percent more worry “a fair amount.”

The real break with progressive orthodoxy in Manchin’s memo comes on climate change, where he insists that the agenda must be “spending on innovation, not elimination.” In the current negotiations, he’s opposing the proposed Clean Electricity Performance Program, which would essentially pay utilities to eschew burning coal or natural gas. But he is open to various production subsidies that aim to increase the availability of zero-carbon energy, as long as they include support for efforts to generate zero-carbon electricity from coal and natural gas via carbon capture and sequestration.

This last point is probably a pipe dream, but it’s easy enough to see why a senator from West Virginia doesn’t want to formally sign a death sentence for the coal industry. And Manchin’s insistence that climate policy should focus on maximizing clean-energy production rather than penalizing fossil fuel use is perfectly in line with public opinion, where ballot initiatives to tax emissions keep failing even in blue states.

Manchin is a proud gun owner, a supporter of the Hyde Amendment — which bans the use of federal funds to pay for abortion — and someone who talks exclusively about brass-tacks economic issues rather than racial politics or other social and cultural matters. He seems like the kind of guy who wouldn’t introduce himself with his pronouns. And however you feel about this personally, it’s proved to be a winning formula in the very red state of West Virginia, where Manchin massively overperforms national Democrats.

Sinema, by contrast, has all the personal style cues of a stereotypical urban educated liberal, and breaks with her party primarily to defend unpopular business interests.

The party isn’t going to uniformly Manchinize, and it shouldn’t, since many Democrats have constituencies that are more diverse and more urbanized than Manchin’s. But going halfway to where he is could put states like Ohio, Iowa and North Carolina within striking distance. Resurrecting a Manchin-style wing of the party could be a godsend for the Democrats in large swaths of the country. It wasn’t so long ago, after all, that Democrats held 60 Senate seats, including from Arkansas, South Dakota and Alaska. That achievement required ideological compromise, but having enough votes to overcome the filibuster also put bigger policy changes on the table like the Affordable Care Act and the Dodd-Frank financial regulation overhaul.

If you’re a Democrat and you want to break with progressive orthodoxy, you should do it in a way that’s attentive to public opinion or to specific local concerns. Given the varied set of positions that Sinema, a former Green Party activist and onetime progressive firebrand in the Arizona Senate, has had over the course of her career, it’s a little hard to know where she’s coming from in her latest political incarnation. But her brand of renegade politics is fundamentally a dead end, in ways that should be appreciated even by those of us who think the Democratic Party would benefit from a bit more Manchinism.