On Thursday in the United Kingdom, Jeremy Corbyn’s Labour Party suffered its worst defeat since World War II. For Labour, it was an electoral apocalypse.

American pundits with a only cursory understanding of British politics are making simplistic comparisons, suggesting that Corbyn’s landslide loss dooms Elizabeth Warren and Bernie Sanders. The reality is that we don’t know if it means anything at all. What we can say is that Corbyn’s train-wreck candidacy confirms that it’s not a good idea to nominate someone who is liked by only 23 percent of voters (who knew?) and that there are electoral risks to far-left candidates. (It’s worth noting that Corbyn is much further left than Warren or Sanders.)

While Americans scramble to think about what the British election means for the Democratic primary, few have stopped to consider the opposite: How have American politics warped British elections? It turns out that to understand this week’s British election, you also have to look to Washington.

The United Kingdom and the United States each benefit considerably from their “special relationship.” Nonetheless, that relationship is asymmetric. The United States is much more powerful, so when push comes to shove, Britain needs the United States more than the reverse.

British prime ministers therefore have to walk a diplomatic tightrope. To maximize British power, they need to be close to the U.S. president. But if they get too close, they can be seen as vassals of the United States, lackeys subservient to Washington. And when they are viewed that way and the United States messes up, that combination can destroy British prime ministers in ways that resonate for a generation.

In 1997, Tony Blair promised a more centrist version of the Labour Party, the so-called Third Way. The idea was to reconcile Labour’s divided wings into a consensus that could create a big-tent party and appeal to potential crossover voters. Boy, did it work. Blair won a landslide, securing 418 of the 659 seats that year in Parliament, a substantially bigger margin than Boris Johnson won Thursday. The electoral strategy of “Blairism” was vindicated.

But Blair, ultimately, was not. Across party lines, Blair has become toxic. Just 19 percent of Brits have a favorable opinion of him. And almost all of that fall from grace can be traced to one decision: backing the Iraq War in 2003. He became widely seen as George W. Bush’s lapdog, wagging his tail as he followed the United States into a foreign policy quagmire. His fall took Blairism down with him.

You can’t explain the rise of Corbyn without the fall of Blair. Crucially, Corbyn aggressively opposed the Iraq War. Today, when big-tent Labour moderates argue that they could appeal beyond the hard-left base that Corbyn has wrapped around his finger, they often face as serious an accusation as the Labour left can muster: that they are secret Blairites.

The policies and the electoral coalition needed for Labour to win have shifted considerably since 1997, not least because Brexit unleashed a seismic shift in British politics. (For example, Blair’s old seat, Sedgefield, flipped from Labour to Conservative on Thursday). But because of one decision originating in Washington and confirmed in London 16 years ago, Labour Party activists continue to dismiss the value of big-tent politics. The Iraq War changed British politics for a generation. And Boris Johnson was the beneficiary of that shift this week.

Now, it’s Johnson’s turn to walk the special relationship tightrope. As Britain downgrades its relationship with the European Union, the importance of the U.S.-U.K. bond will necessarily increase. If you move away from Brussels, it’s crucial to move closer to something else to fill the void. Right now, President Trump is that something else.

In response to the Conservative victory, Trump tweeted his support for a quick post-Brexit trade deal with Britain. Johnson is salivating over that potentially momentous symbolic victory. Conversely, Trump doesn’t need the trade deal. He can and will try to bully Britain into submission. And key sticking points for Brits, from agriculture to the National Health Service, could become Johnson’s Blair-style quagmire. As Johnson was so fond of saying about Brexit: Many believe that “no deal is better than a bad deal.”

That’s especially true because Trump is even more toxic than Blair is in Britain, with just 18 percent supporting the U.S. president. At the recent NATO summit in London, Johnson avoided one-on-one photos with Trump so that the image couldn’t be used against him in the campaign. That’s Britain’s new Catch-22. For post-Brexit trade, Johnson needs Trump. But if Johnson is seen as a lapdog to a reviled president, it could doom him — not just with the British public, but also with Trump’s successor, should Trump lose to a Democratic challenger next year. And that could derail the special relationship, too.

Just like Tony Blair in 1997, Boris Johnson just won an electoral landslide. But will he make the same mistakes in navigating the special relationship that destroyed Blair and led to the Corbyn debacle? We’re about to find out.

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