One of Europe’s most interesting political stories is currently unfolding in Slovakia as the country readies itself for a presidential election later this month. Defying the common view of Central Europe as a backward region captivated by charismatic nationalist leaders with a soft spot for Russia, Slovaks are about to elect a squarely pro-Western, liberal figure—and a woman, no less!—to their highest office. Zuzana Čaputová is backed by a coalition of new reformist center-right and center-left parties which stand a good chance of taking over the government after next year’s parliamentary election.

Thanks to its small size and a relatively fluid party system, the post-communist country has become a small laboratory of how centrist politics can respond to challenges of the populist era. Slovakia has been in the midst of all the major debates animating the Western world: from the question of immigration and asylum policy in 2015, to the apparent corruption of political elites, to the pressing geopolitical challenges driven by the country’s proximity to Ukraine and Russia.

Yet the ongoing political realignment and the rise of an aggressive moderate reformism have been catalyzed by the murders of journalist Ján Kuciak and his fiancée Martina Kušnírová in February last year. After years of corruption scandals under the watch of the ruling, left-populist Smer party, the country saw protests on a scale comparable to the Velvet Revolution of 1989. Smer’s leader and then-Prime Minister Robert Fico tried to dismiss those as organized and funded by George Soros. That strategy backfired since the mobilization cut across demographics and geography, and reflected a genuine sense of discontent with the country’s status thirty years removed from the fall of communism.

The wobbly coalition of Smer, Slovak nationalists, and a small Hungarian party went through a government reshuffle, forcing Mr. Fico out last spring. But that was only the beginning. New political parties emerged, one on the center-Left (Progressive Slovakia) and another on the center-Right (SPOLU-Civic Democracy), both backing Ms. Čaputová in her run for president.

Ms. Čaputová is an attorney who built her career fighting state-connected mafia bosses in courts. Although recognized as Slovakia’s version of Erin Brockovich, her campaign initially struggled to take off. At the end of January, she was trailing in the polls behind three or four other candidates, making Slovaks wonder (this writer included) whether her candidacy was viable at all. What has happened since is nothing short of spectacular: Her support skyrocketed from around 10 percent to over 50 percent in some polls, prompting speculation that she could outright win in the first round scheduled for March 16.

While that is unlikely, the election is hers to lose, regardless of whom she faces in the second round. In retrospect, the key to her success seems simple: She is a very strong candidate. Articulate, charismatic, and exuding warm-heartedness, her career path pits her against Slovakia’s corrupt status quo, without having to resort to the rhetoric of elite vs. ordinary people that is emblematic of populism. As a result, the attacks against her appear more and more desperate. Because Ms. Čaputová received the Goldman Environmental Prize in 2016 for her activism, Smer resorted to a vile anti-Semitic conspiracy theory picturing her as a puppet of international Zionism.

These smears indicate that Slovakia is still very much divided. The decline of Mr. Fico’s Smer and the rise of the moderates has not eroded the support of Slovakia’s Neo-Nazi party, whose leader, Marián Kotleba, is also running for president. Another, more promising nationalist candidate in the race is Štefan Harabin, former Justice Minister and a current Supreme Court justice. Echoing Donald Trump’s bombastic, larger-than-life style and lack of scruples, Mr. Harabin took months of medical leave from the court to kick off his campaign, without damaging his standing among voters. He promises to stretch the powers of the office (normally quite constrained) to their limits, in part by ending the EU’s sanctions against Russia.

It is quite likely that Ms. Čaputová will face Mr. Harabin in the run-off, instead of Smer’s more respectable and polished candidate, Maroš Šefčovič, the current Vice President of European Commission for Energy Union. But Mr. Harabin’s populism risks ringing hollow in a political environment sensitized to questions of the rule of law and fairness. No matter how much he depicts himself as an angry outsider, for decades he was among the most powerful men in Slovakia’s judiciary and bears direct responsibility for its current malaise.

And the presidential election is likely only the beginning. Far more consequential will be the parliamentary election next year, and, specifically, what forces will replace the declining Smer. In addition to the two new parties, polling jointly at almost 10 percent, the departing president, Andrej Kiska—a widely popular figure and a staunch Atlanticist—is rumored to be considering party politics, either as a leader of a moderate, pro-Western coalition of existing parties or as a founder of a new reformist party of his own.

The Guardian’s Natalie Nougarède was among the first Western observers to note the potential of these events for a broader turning point in central Europe. If the current political reshuffling ushers in a stable, reformist government next year, “the children of those who successfully fought for democracy in 1989 will have demonstrated that ‘truth’ and ‘decency’ (key slogans they use) can yet again be victorious.”

While nothing is preordained, there are reasons for optimism. Unlike in wealthier, better functioning democracies such as the neighboring Czech Republic, Slovaks understand that they have no time for complacency. The country’s small size, tight social connections, and lack of rigid party structures facilitates political realignments and mobilization. And, unlike in, say, Hungary, Slovakia’s politics is not defined primarily by the traumas of its past but by the promise of the future.

These dynamics are not just interesting in their own right or because of their implications for the strength of the transatlantic partnership. Most importantly, they illustrate the broader political changes currently underway in the Western world. The divide between Ms. Čaputová and Mr. Harabin is one between “open” and “closed” society, forward-looking dynamism and nostalgia, or between cosmopolitanism and ethnic particularism. The trap that Smer’s Mr. Šefčovič has fallen into is that he is trying to be both. His personal sensibilities and style, as a Brussels technocrat in good standing, are as worldly and serious as anybody’s. Yet Smer’s electoral base, which he is trying to reach, is more rooted than cosmopolitan, responding well to messages of nostalgia and stability.

In contrast to U.S. millennials’ supposed love affair with socialism and the rhetoric heard recently at CPAC, Slovakia’s example suggests that the polarity between “socialism” and the “free market” is largely dead in a country that experienced actual socialism first hand. As the centrist coalition behind Ms. Čaputová illustrates, the abstract dichotomy between “small” and “big” government does not apply much anymore, both in terms of substance and electoral appeal.

That is not to say that there is no disagreement over specific policies. Rather, the importance of such differences pales in comparison with the question of whether Slovakia can become a normal European country. Furthermore, the possible solutions to economic and social challenges facing Slovakia—from aging to low levels of R&D to a large and poorly integrated Roma population—do not map neatly into the Left/Right dichotomy.

By contrast, cultural divides, including on questions of cultural and social conservatism, are not going anywhere, even if they seem somewhat muted at the moment. Ms. Nougarède was right to observe that last year’s protests cut across such divides, as organizers “reached out to—rather than shunned—socially conservative parts of the population.” Yet, Ms. Čaputová has been far more outspoken about her liberal positions on same-sex marriage and adoptions by same-sex couples than most candidates before her. That is bound to deter some of the more conservative Catholic voters who would otherwise stand on the “open” side of the divide with her. At the same time—and herein lies a lesson for social liberals in the West – she has never flaunted her views simply to “own” socially conservative audiences. Quite the contrary.

It was not a long ago that I wrote in these pages about Slovakia’s wobbly geopolitical allegiances and its emboldened, Kremlin-loving nationalists. While those have yet to be defeated, for the first time in years it feels like it is not them but the country’s pro-Western, reformist forces that have wind in their sails. We will see soon whether this momentum can be sustained beyond the current presidential race.