THE HAGUE, Netherlands — The economy is up, unemployment is down and some Dutch prisons are so empty the government has been renting out cells.

So why do polls indicate that the Netherlands’ ruling parties are set to suffer big losses before a March 15 national election, while the party of right-wing anti-Islam lawmaker Geert Wilders appears poised to make substantial gains?

“It’s not the economy, stupid,” Professor Gerrit Voerman of the University of Groningen said, tweaking the campaign message Bill Clinton used in his successful 1992 march to the White House. Instead, Voerman said, “It’s about identity.”

Wilders’ campaign slogan sums it up: “The Netherlands ours again!”

The nationalist refrain, which echoes U.S. President Donald Trump’s campaign call to make America great again, is a theme that could dominate elections in two other European nations this year — France and Germany. How Wilders’ Party for Freedom fares next month should provide an indication of the prospects for fellow far-right nationalists Marine Le Pen, the presidential candidate for France’s National Front party, and Frauke Petry of the Alternative for Germany.

In the Netherlands, pollsters predict that Prime Minister Mark Rutte’s People’s Party for Freedom and Democracy will lose about 15 of the 40 seats it holds in the 150-seat House of Representatives. Wilders’ party,  which currently has 12 lawmakers in the chamber, is on track to become one of the biggest, if not the biggest, parliamentary faction, despite a recent decline in polls.