Jean-Luc Mélenchon’s left-wing alliance elected 142 MPs to France’s National Assembly on Sunday. In some ways this was a success: the broad left more than doubled its number of MPs and helped strip President Emmanuel Macron of his majority, though it also fell way short of the 289 seats needed to make Mélenchon prime minister. In the last such election five years ago, Mélenchon’s France Insoumise had taken seventeen seats, barely more than the number needed to form an independent group; this time, there were seventy-two, making up half of the overall left-wing bloc.

That alliance of parties is known as Nouvelle Union Populaire Écologique et Sociale (NUPES). Formed in May, it brought together forces that have often had significantly divergent agendas. By the terms of their pact, they will collaborate in parliament to pursue the policies in their common program — largely based on the one Mélenchon ran on in April’s presidential election — but maintain their independence where they differ. Among other NUPES forces, the once-mighty Socialist Party won twenty-eight seats on Sunday, the Greens twenty-three, and the French Communist Party twelve.

NUPES’s candidates and program were largely drawn from France Insoumise, with Mélenchon’s 22 percent score in the presidential contest affirming his leadership role on the Left. Yet there are already questions as to how long the alliance can last.