Several trends were apparent in the results of the EU parliamentary elections that took place from last Thursday through Sunday across 28 European countries. Right-wing populists surged, though not quite as much as some had predicted. Support for the established center-left and center-right continued to sag. Green parties did very well and appear to be surpassing social-democratic parties on the left.

These and many other conclusions became clear as soon as the votes were counted because the parliamentary systems that prevail in Europe encourage the proliferation of parties, with public opinion reflected in the relative strength and weakness of each. In countries like the United States, where the electoral system strongly favors the creation and perpetuation of just two competitive parties at the national level, things look very different. In such systems, strong differences in opinion get subsumed into the parties, with each of them containing multiple jostling groups and agendas, and the tensions and clashes among them usually taking place largely out of sight, behind the scenes.

But what if such differences were forced into the open in the way they are in multi-party systems? How would American politics look if the major factions that make up the Republican and Democratic parties became independent parties? And what do we learn about character of the tensions within the existing parties by envisioning them as conglomerations of restive factions?

It makes sense to think of the Republicans and Democrats as each containing three factions that, in a multi-party system, could thrive as independent parties. That makes for a total of six imaginary American parties. Let's start with those that might exist on the right:

The Populist-Nationalist Party: This faction — anti-immigrant, skeptical of free trade and big business, suspicious of the deployment of American military force abroad, strongly nationalist — had little influence within the national Republican Party from the 1950s through the administration of George W. Bush. Donald Trump's 2016 campaign activated this partially dormant paleo-conservative faction and its voters in the post-industrial Midwest and low-density regions of the interior, who rallied to his side. If it were an independent party, the populist-nationalists would be the American counterpart to Marine Le Pen's National Rally (former National Front) in France, Matteo Salvini's League in Italy, and Viktor Orbán's Fidesz in Hungary.

The Internationalist Conservative Party: Pro-immigration, pro-free trade, favoring low income and corporate taxes, willing and even eager to use American military might to transform the world in our economic and political image, this faction is favored by big business, major GOP donors, upper-middle-class and wealthy white suburbanites, and (at least until Trump's election somewhat complicated matters) the bulk of the Republican Party establishment, including its leading think tanks and media messengers. If an independent party, the internationalist conservatives would overlap with many of Europe's center-right parties, albeit with a far greater skepticism about government provision of social services.

The Religious Right Party: Strongly anti-abortion, anxious about threats to the religious freedom of traditionalist Christians and Jews, prioritizing the appointment of staunchly conservative jurists to the nation's courts, this faction has been a strong member of the Republican electoral coalition since Ronald Reagan's 1980 presidential campaign. Its core is white evangelical Protestants, but it also includes conservative churchgoing Catholics, and orthodox and ultra-orthodox Jews. If an independent party, the religious right would play a role analogous to the one played by the far-right ultra-orthodox and settler parties in Israeli politics — providing essential support to more secular-nationalist parties of the right in return for constant forward movement on the issues that matter most to it.

Viewed in this way, the GOP looks less coherent under Trump than it was from Reagan through the administration of George W. Bush, when the party needed to contain just two competing factions (the internationalists and religious right). Now there are three potentially independent parties jostling for power under the Republican umbrella.

Yet thinking of it like this may be misleading. In a parliamentary system, clashing parties can be lured into forming a government by offers of power through the control of ministries and the policy portfolios they oversee. Something similar has happened to the GOP under Trump. The internationalist conservatives have lost on immigration and trade, but they have benefitted greatly from an enormous corporate tax cut. Some members of the religious right, meanwhile, are disturbed by the administration's hard line on immigration, but they have been placated by the president's rapid-fire appointment of hard-right judges to the federal courts, as well as other moves meant to advance a religious-right agenda.

And of course, underlying everything is the president's constant effort at demonizing the opposition. The GOP's three factions and potential parties may disagree about a lot, but they are united in loathing and fearing economic and cultural liberalism.

Turning to the left, there are certain parallels with the right, but also important differences.

The Social Democratic Party: This faction supports a long list of policy proposals, including sharply higher income taxes and a wealth tax, single-payer health care, free college tuition, and decarbonization of the economy. Whether thinking of itself as a movement toward socialism — as Sen. Bernie Sanders (I-Vt.) and Rep. Alexandria Ocasio-Cortez (D-N.Y.) sometimes do — or an effort to more adequately regulate capitalism — as Sen. Elizabeth Warren (D-Mass.) prefers — this faction's agenda, which is supported most strongly by young, white, and highly educated voters, is incredibly ambitious, aiming to remake much of the economy from the ground up while drastically shifting the priorities that have dominated the Democrats since the late 1980s. With its focus on economic issues, this faction also places relatively little emphasis on identity politics and the culture war while also viewing some free trade policies and much of America's hawkish foreign policy consensus with suspicion.

The Internationalist Progressive Party: Highlighting a more cautious, incremental, and technocratic approach on economic policy, this faction nonetheless shares many goals with the social democrats, while adding a strong emphasis on identity politics and enthusiasm for prosecuting the culture war from the left. (Think Sen. Kamala Harris (Calif.) or South Bend Mayor Pete Buttigieg.) This includes support for immigration policies that stop short of open borders but nonetheless push quite far in that direction, along with enthusiasm for free trade agreements, the expansion of international law, and a pivotal American role in enforcing it using military might. This faction enjoys broad support in urban areas, high-density suburbs, and minority communities.

The Centrist Working-Class Party: Older, whiter, less educated, and more likely to be found in the unionized, post-industrial Midwest than the members of the other left-leaning parties, this faction strongly supports Social Security, Medicare, and other social programs that date to the mid-20th century, but is more skeptical about viability or wisdom of expanding the safety net much further. Its members also tend to be more conservative on culture war issues, express some nationalist sympathies, and fear that high rates of unskilled immigration will depress wages and increase competition for lower-skilled jobs.

The current frontrunner in the 2020 Democratic primary contest — Joe Biden — is very clearly positioning himself as a champion of this centrist, working-class party, in part by dissing priorities favored by the other factions: The policy goals of the social democrats are too ambitious, while the culture war stance of the internationalists is too polarizing. Though this might be politically smart, it's unclear how a victorious centrist could unite the three mini-parties of the left into a coherent governing umbrella party.

This might not be answerable until after an incoming President Biden has chosen his Cabinet and set policy priorities for his administration. (Few in 2016 foresaw the precise way the Trump administration would juggle the competing factions of the GOP.) Still, there is cause for concern. While the social democrats and internationalists both loathe Trump and the Republican Party enough to unite in negative partisanship that mirrors the broad-based anti-liberalism of the right, the centrist faction is in part defined by a longing to compromise and reach consensus with reasonable Republicans. Trump is the problem, the centrists insist, not his party. Once Trump goes, it will once again be possible to reach deals across the aisle and govern in a genuinely bipartisan way.

Whether or not that proves to be true — and I highly doubt it will — the very fact that Biden and his faction believe that it's possible is likely to make it more difficult for Democrats to unite. Anti-conservatism simply isn't as widespread or potent in American politics as anti-liberalism, which means that the Democrats run the greater risk of acting like three separate and competing parties.