Since Donald Trump’s 2024 victory, the Democratic Party has been embroiled in a vicious internal conversation over moderation. One camp argues the party has moved too far left on cultural issues, particularly immigration and trans rights, and needs to tack to the center. Their opponents argue such a strategy will alienate core voters without making inroads among MAGA faithful. This week, the anti-moderation camp claimed vindication—citing not US developments but the resignation of UK Prime Minister Keir Starmer.
Starmer’s Moderation Strategy and Its Mixed Results
Starmer, more than any other center-left politician globally, actually executed what the pro-moderation camp proposes—moving the Labour Party to the center on social issues, especially immigration. Yet his numbers collapsed, and Labour suffered humiliating electoral defeats in special and local elections, while the far right and far left surged. For anti-moderates, the lesson is straightforward: a Democratic party that does something similar is due to defeat.
“Starmer’s resignation is a warning,” Adam Bonica, a political scientist at Stanford University, wrote this week. “In a moment like this, tacking right isn’t the safe play, it’s the thing that sinks you.”
Moderates argue this misreads the evidence: Starmer won power due to moderate politics, and his declining numbers stem more from economic fundamentals than culture. “His cultural moderation has been an asset to Labour in getting closer to where the mainstream of voters are,” Claire Ainsley, a former Starmer adviser and current director of Project on the Center-Left Renewal at the Progressive Policy Institute, told me.
When Moderation Helped Starmer
After the UK’s 2019 elections, Labour was in the wilderness. Led by hard-left socialist Jeremy Corbyn, the party suffered its worst performance in roughly 100 years. Corbyn’s net approval rating was negative 40, while Prime Minister Boris Johnson’s was minus 12. Corbyn’s foreign policy radicalism and scandals about antisemitism contributed to this perception.
When Starmer won the Labour leadership in 2020, he pursued a strategy of “decontamination,” repositioning Labour as a mainstream party. He apologized for Corbyn’s handling of antisemitism, endorsed increased defense spending, and mocked his predecessor. In the 2024 election, Labour won nearly two-thirds of seats, the third-largest majority in party history. Voters who switched from Conservatives to Labour were vastly more likely to say Labour respected people like them under Starmer rather than Corbyn.
However, two caveats exist. First, the Conservative Party had been in power for 14 years with a shattered reputation. YouGov data showed Labour supporters were overwhelmingly more likely to cite getting rid of the Tories rather than affirmatively backing Labour. Second, Starmer’s moderation on cultural issues specifically did not drive the perception that Corbyn was too radical; his detoxification focused on foreign and economic policy. Labour voters’ top issues were overwhelmingly economic (cost of living and healthcare).
When Moderation Hurt Starmer
Almost immediately after taking office, Starmer’s numbers dropped. Nearly everyone agrees the reason: he failed to deliver promised quality-of-life improvements. “There’s been no respite on the cost of living, with food and energy inflation remaining high, while the NHS and public services have not really improved,” YouGov’s Dylan Difford wrote this week.
His tack to the center on cultural issues exacerbated the fallout, especially on immigration. In summer 2025, Starmer gave a speech arguing mass cultural change was turning Britain into an “island of strangers” and announced aggressive cuts to legal immigration. By May 2026, net migration fell to the lowest since the Covid-19 pandemic. Yet his numbers continued to fall. Reform UK—an extreme anti-immigration party—surged, becoming the most popular party. Disillusioned left-wing voters defected to the Green Party, which took an unapologetically pro-immigration stance.
“They didn’t win back those voters that left for reform—and they alienated progressives,” Tarik Abou-Chadi, a political scientist at Oxford, told me. A study of the “Island of Strangers” speech found it decreased voting intentions for Labour by 1.2 percentage points and resulted in a 3.9 percentage-point haemorrhage in support from Labour’s own former voters without attracting new supporters.
Lessons for the US
The US and UK political contexts differ importantly. The UK system allows viable third parties; left-wing Americans have no such option, making it less likely that moderation could cost Democrats a huge chunk of their base. Also, US legislators have more autonomy to create individual brands that might benefit from moderation.
The most relevant lesson is that successful moderation is more complicated than simply adopting median voter positions. When Starmer’s moderation worked, it was because he cultivated a perception that Labour was no longer the same party under Corbyn. But this didn’t work as a governing approach. His focus on poll-tested cultural policies to win over far-right voters was premised on a myth that large numbers would vote center-left. It also made him seem inauthentic and unprincipled, and he struggled to articulate a new North Star for the party.
“Positioning himself as the custodian of a phantom center, Mr. Starmer treated most Labour supporters with contempt,” British journalist Samuel Earle wrote in the New York Times in May. “Yet he has also seemed too nervous to outline what that project might be.”
This might be the most salient lesson for American politics: compromising one’s own core identity is almost certainly a losing strategy. Political parties need affirmative visions that animate core supporters and create a clear sense of what they stand for. Moderate politics can provide that vision, as Bill Clinton and Tony Blair showed in the 1990s. But Keir Starmer didn’t—and both he and his party are paying the price.
