It’s a little too easy for liberals and globalists to breathe a sigh of relief at the victory of Emmanuel Macron in France. His win averts a short-term crisis over the terms of France’s participation in the European Union, but as both the populists and their antagonists have discovered, victory isn’t everything. You also have to govern.

It hardly seems fair, but, to accomplish anything, Macron will immediately have to win a third electoral victory after succeeding in two rounds of presidential elections. The early June vote for legislative seats will pose a serious challenge for his sparkling new party, En Marche!, which announced a slate of candidates, many of them newcomers to politics, this week. And while Macron needs to find a majority, or a workable coalition, the National Front’s Marine Le Pen has a much lower bar for success. It is projected to win a only handful of seats, but with just two now, any gains will be spun as acceleration of the far right’s political movement, positioning the party to run again in the next presidential election.  

Meanwhile, Macron’s bold ideas for deepening European integration must overcome a skeptical Germany. Chancellor Angela Merkel is up for re-election in September, and her government has ranged from noncommittal to actively opposed to parts of Macron’s economic agenda. Even Germany’s defense minister took the time to snipe at Macronomics, saying in the wake of the French vote, “We can’t redistribute wealth in Europe before we create it,” according to the Economist. Macron faces a rising economic tide—Europe is, for once, doing fairly well—but the handful of electoral victories by centrists doesn’t change the political reality that most reform in Europe only happens in the wake of crisis.

Where Macron is arguably more fortunate is in the absence of strong nationalist media in France. Coverage of the cyber attack on Macron’s campaign was thin in France and driven largely by U.S. right-wing voices. Le Pen, who operates the most boring Twitter account of any nationalist leader, should look to the Netherlands’ Geert Wilders for advice. Despite serving in parliament for nearly two decades, Wilders still positions himself as the ultimate outsider, helped along by his aggressive exploitation of the modern media. He can use his power base in the Netherlands to hit at Merkel in Germany and collaborate with like-minded extremists like Iowa Representative Steve King. The fragmented Dutch political system means that other parties can form a government without him, but doing so is no easy feat. “Day by day we struggle on,” said Mark Rutte, the caretaker prime minster who was lauded for overcoming Wilders in March but has yet to form a government.

Victory has proved no easier for the populists, where they have found it. The far-left Greek party Syriza rode a narrative of rejection of creditor-imposed austerity to political victory in 2012. But governing has tested that narrative. As Stathis Kalyvas writes, Prime Minister Alexis Tspiras's decision to double down on his rejection of creditors’ terms in 2015, when he knew he would have to accept them anyway, cost his country billions. Tspiras has managed to hang on to power, but his chaotic management has allowed an opening for an energetic new challenger, Kyriakos Mitsotakis, to gain strength, and he and his traditional New Democracy party are well-positioned to take over the next time Tspiras stumbles.

A theme connecting both Syriza and Macron is the need for what the historian Timothy Garton Ash calls a simplistic, emotional narrative. That's the only way to cut through the noise in an era of fragmented media. But they show its limits as well. The message that united two-thirds of French voters behind Macron was to oppose the National Front, a narrative so powerful that the sitting French ambassador to Washington got on the radio to compare a Le Pen victory to Vichy-era collaborationism. But Macron needs a new message for legislative elections, and the call for European integration isn’t nearly as uniting. As Le Pen likes to remind anyone who will listen, France voted down the proposed EU constitution in 2005.

The leader who has best embraced this challenge is Theresa May in Britain. She is no one’s definition of a populist, but she has embraced the rabble-rousers’ love of clear and emotive rhetoric. She has accused the EU of meddling in her election, cleverly placing her on the outside of the club she has chosen to leave. Macron’s victory, she says, requires a strong mandate for her in response. “Every vote for me and my team will strengthen my hand in those Brexit negotiations.” Never mind that a Le Pen victory would have been much worse for May, by setting the European building on fire while May tries to calmly head toward the exit.

The difficulty for May will be to ensure that this moment, after Article 50 and before consequences, is not the apex of her political life. Her Conservatives have consumed the political vitality of the U.K. Independence Party and face a vacuum from the Labour Party. But, as is unfolding in Greece with the revitalization of New Democracy, Labour will sooner or later have an opportunity to shrug off its anemic leadership, and when it does, it’s likely to face a government in need of a new message to explain why it’s still relevant. May’s political strategy resembles eternal war with Brussels, but, with Brexit moving Britain outside of Europe’s trading zone and requiring agreement to get back in, that combat could bring real economic consequences for May’s voters. That will leave a wide opening for an opponent to try to rewrite the post-Brexit British story.

In the U.S., too, the economic nationalists are struggling with power. Donald Trump's electoral story about the victims of establishment politics didn't coalesce into a positive vision for the economic reforms his Congress has been trying to enact. And as a political leader, Trump has been unable or unwilling to impose order on the legislative chaos, a problem clearest when it comes to health care. If there's any real threat to Trump now, it's from deep-red congressional districts turning against him because their representatives’ years of promises to repeal Obamacare failed the moment the Republicans gained control of the presidency. If that happens, the party will split over control of the narrative of economic victimization.

The next data point in the great live-action political science experiment about populism is likeliest to come in Italy. The center-left leader Matteo Renzi would like to pull a Theresa May and transition from unelected prime minister to elected. But he has stumbled along the way. While holding the prime minister’s seat he grabbed from a previous party leader, he tried and failed to reform Italy’s election laws, prompting him to step down. Like Macron, he was 39 when he took on the leadership in 2014, but now, as he plots a return to power, his appeal as a fresh-faced outsider has waned.

In the meantime, the anti-establishment Five Star Movement has gained political potency, and would rival Renzi’s party for votes were an election held soon. Five Star is an embodiment of recent populist trends. They have embraced fake news with gusto, creating a media machine to gin up useful stories. Its leader, the former comedian Beppe Grillo, will not personally seek to become prime minister, but will control the government from behind the scenes. His supporters have questioned the European order and backed protectionism.

The obvious question is, after they smash the establishment that the likes of Macron and Merkel have so lovingly built, what will come next? To quote Donald Trump, “I thought it would be easier.”