It is a great historical irony that, at the very moment the once mighty French Communist Party enters its last twilight, it has at long last backed a candidate who, if Jean-Luc Mélenchon’s surging poll numbers are to be believed, has a serious chance of winning France’s impending presidential elections. That arguably the most powerful of Western Europe’s postwar communist parties (and at one time France’s largest party) today hangs on to a handful of city halls in its former industrial strongholds and, no longer capable of running a credible presidential candidate of its own, instead rallies other organizations in support of a candidate with no association with the party (an ex-Trotskyist to boot!) is testament to how history has passed orthodox communism by. Nonetheless, that so fiery a critic of capitalism as Mélenchon has come so close to France’s highest elected office points to mounting dissatisfaction with France’s political institutions and neoliberalism alike. Communism may be dead, but the struggle against capital has manifestly taken on new life in France.

Mélenchon’s lifetime of political activism and public service bridges two distinct worlds for the French left: the period of creative possibility following May ’68, on the one hand, and the current moment of disarray and reconstruction in the wake of François Hollande’s disastrous five years as president, on the other, an arc traced by the Socialist Party’s long march to and in power. Born in Tangiers in 1951, his parents a postman and an elementary-school teacher who were themselves born in French Algeria of Spanish immigrants, Mélenchon later moved with his mother to Franche-Comté. Politicized as a high-school student during May ’68, Mélenchon joined the Lambertist strand of French Trotskyism—a small but important piece in the richly contested tapestry of the French left in the 20th century, which pursued a strategy of infiltrating political parties and unions known as “entryism,” and whose ranks counted figures like former Socialist prime minister Lionel Jospin, former head of the Force Ouvrière labor union Marc Blondel, and current first secretary of the Socialist Party (PS) Jean-Christophe Cambadélis. Finding work as a schoolteacher and journalist, Mélenchon also participated in the 1970s workers’ self-management struggle at the LIP watchmaker factory.

Mélenchon joined the Socialist Party (PS) in 1976 (only quitting the Lambertists around 1979), and François Mitterrand’s victory in the 1981 presidential elections helped accelerate his rise through the party’s ranks. He represented the southern Paris suburbs as departmental councilor and senator, and served in Jospin’s cabinet in the early 2000s. Always on the left wing of the PS, he is a battle-scarred veteran of its always-contentious party congresses, a constant opponent of the Socialists’ successive compromises with the market since 1983. Though Mélenchon supported the Maastricht Treaty that initiated the transformation of the Common Market into the European Union, setting it on track toward a common currency in France’s 1992 referendum, he rapidly disavowed it to become one of the few members of one of the most strongly Europhile parties in Europe to consistently oppose the EU for its neoliberal tropism. Opposed to the Treaty of Amsterdam in the late 1990s, Mélenchon campaigned against his own party during the French referendum on the European Constitution in 2005.

Convinced that the PS had sailed too far into free-market-friendly seas, Mélenchon quit the party after Ségolène Royal’s loss to Nicolas Sarkozy in the 2007 presidential elections. Taking inspiration from Germany’s newly created Die Linke formation, Mélenchon founded the Parti de Gauche in 2008 in the hopes of building an authentically left-wing political force in the void left by a withering French Communist Party (PCF) and an increasingly centrist PS. Already in the 2012 presidential elections, Mélenchon’s capacity to mobilize large, enthusiastic crowds and his unexpectedly strong showing in the first round (finishing fourth, with 11 percent of votes cast) suggested he had rightly discerned room on the left and was himself capable of occupying it.

Looking ahead to 2017, Mélenchon regularly organized rallies and, though he had backed Hollande in the second round of the 2012 election to block Sarkozy’s reelection, he sharply criticized Hollande’s Socialist government. Prescient once again, correctly sensing the same accelerating loss of confidence in traditional parties that has fueled the centrist candidate Emmanuel Macron’s meteoric ascension to odds-on favorite in this year’s race, Mélenchon eschewed the 2012 Front de Gauche party alliance and, looking to models like Spain’s Podemos, built a movement along participatory-democratic lines called La France Insoumise (Rebellious France). His program was elaborated and voted on by tens of thousands of activists. La France Insoumise maintains a dynamic online presence, encompassing, notably, a video game released several days ago called Fiscal Combat (in which a Mélenchon avatar shakes down the rich for cash). Just as in 2012, Mélenchon’s formidable oratorical talents have helped draw impressive crowds to his rallies.

There is probably no other prominent political figure in France who has fought harder and more publicly against far-right leader Marine Le Pen than Mélenchon. It’s a genuine pleasure to watch him skewer the National Front (FN) leader during their always-epic confrontations on French television’s staple political debate shows. Showing foolhardy courage, Mélenchon threw himself into the race against Le Pen in the 2012 legislative elections in a district in northern France before stumbling badly, finishing behind both Le Pen (who captured 42 percent) and the PS candidate (at 21 percent).

Were Mélenchon to win this year’s elections—and were he to enjoy a parliamentary majority with which to govern (perhaps an even bigger if)—his program would set France on the most resolutely leftward course of any developed country since the French left came to power in 1981. A good part of his platform, laid out in impressive detail in the manifesto L’avenir en commun (The Future Together), is classically Keynesian, statist, and redistributive: a substantial boost to public investment; raising the minimum wage, already the fifth-highest in the world, to over $1,800 a month; reducing the workweek to 32 hours; lowering the retirement age to 60; and a sharp increase in taxes (with a startling 90 percent top marginal tax rate on annual incomes above 400,000 euros, about $430,000). Critical (like others on the left and in the center) of the Fifth Republic’s concentration of powers in the hands of the president in a kind of elective monarchy, he promises to reform French institutions through a constitutional convention charged with designing a Sixth Republic, one in which parliamentary institutions would be strengthened, proportional representation introduced, presidential authority reduced, and anti-corruption rules bolstered. His program and rhetoric also emphatically embrace contemporary France’s cultural diversity.

But Mélenchon promises a more radical transformation still. Inspired by the décroissance (degrowth) movement which has taken root in France in recent years—a critique of industrial capitalism for its ecological unsustainability—his program proclaims itself to be a blueprint for a new “ecosocialism,” imagined as a wholesale refounding of society and economic life atop sustainable development and a transition to 100 percent renewable energy by 2050.

Some on the left quibble with particular aspects of Mélenchon’s program—the unrealistic level of public spending it would require, for example, or an overly centralized, productivist approach to reform. But there is much in this ambitious road map for economic, social, and ecological transformation to make progressives in France happy—indeed, it shares much in common with Socialist candidate Benoît Hamon’s own similarly décroissance-inspired platform. Hamon and Mélenchon had been fellow travelers of sorts on the PS’s left wing, even joining forces at the 2008 party congress in Reims in an unsuccessful attempt to push the party’s political cursor back away from the center.

It is Mélenchon’s foreign-policy positions that have made it so difficult for some French progressives to embrace his candidacy with enthusiasm. He proposes to pull France out of NATO and pursue a strategy of nonalignment. Mélenchon’s perceived alignment with Russia has provoked particular controversy. He has argued that the West should avoid confronting Russia in places like Ukraine and has approved Russia’s intervention in Syria—though it should also be said that Mélenchon sharply criticizes Vladimir Putin’s authoritarianism, and no evidence of direct ties between Russia and his campaign have emerged.

It’s also hard to pin down just how internationalist this self-described socialist revolutionary really is. Mélenchon’s rhetoric mixes tiers mondisme and muscular nationalism. He calls for moments of silence in honor of Syrian refugees who have died seeking asylum in Europe, and he has promised that France will join the Bolivarian Alliance for the Peoples of Our America, launched by Hugo Chávez and Fidel Castro in 2004. But his campaign also breaks with the symbolic and discursive traditions of the French left and far left: Notwithstanding his trademark red scarf, tricolors are far more in evidence than red flags at his rallies, as is the Marseillaise in the place of the Internationale. In his 2015 book Le Hareng de Bismarck (le poison allemand) [Bismarck’s Herring (The German Poison)], Mélenchon joins reasoned critique of Germany’s capitalist model with a troubling screed deploring an essentialized Germany menacing an equally essentialized French way of life. He has spoken in sharp terms about how some immigrant workers steal jobs from the French and has promised to “give France back to the French”—words that fall on some ears as a bit too close to National Front slogans for comfort.

Most troubling to many is Mélenchon’s at best ambiguous attitude to Brussels. He promises first that France will cease respecting certain EU rules—limits on deficit spending, notably—in order to force a renegotiation of EU treaties along less market-friendly and public-spending-averse lines. If these negotiations fail, Mélenchon will put into action what he calls blithely a “Plan B”—an unspecified alternative that most assume would be a French exit from the EU. For many on the left who remain viscerally attached to the European project, for all its profound neoliberal imperfections, and to the great advances it has in fact brought to Europeans, Mélenchon’s implicit threat to leave is a dangerous and irresponsible gamble—akin to David Cameron’s foolish referendum last year—that risks dynamiting the EU altogether.

Mélenchon’s campaign raises challenging questions. Is he a populist? Setting aside the endless semantic debates that are currently occupying political scientists and pundits the world over, it is noteworthy that Mélenchon himself proudly embraces the label, claiming to speak for le peuple and arguing that elites have amply earned their anger. That two left-wing leaders running on the most detailed, left-oriented platforms endorsed by leading candidates of any Western nation in over a generation are together polling over 25 percent poses the question: Why is it that Mélenchon pulled away from Hamon, and not the other way around? Can Mélenchon win (we might recall that he didn’t perform quite as well as polls predicted in 2012)? And if he does, can he govern?

Mélenchon has thus imposed a terrible dilemma on many French progressives who remain devoted to the European project and wish to renovate it along social-democratic lines. Indeed, just as the election’s gripping and still uncertain narrative has lent this political drama unity of time and place, the architecture of France’s two-round presidential voting system and the anxious uncertainties of an unstable political landscape have created for voters a Cornelian dilemma, an ideological squaring of the political circle: how to stop the FN, reject the Thatcherite revolution promised by François Fillon, and refuse Emmanuel Macron’s proposed reform of the status quo around its deregulatory margins? Cast a ballot for Hamon, a pro-European leftist outdistanced in the polls, or for the Euroskeptic Mélenchon, who amazingly appears to be within striking distance of the Élysée? For such voters, there will be no easy choices this coming Sunday.