Right now Mr. Wilders’s party looks set to win more seats than any other or to come in second. However, he has historically polled better before elections than he has performed in them. Still, after pollsters underestimated the likelihood of both Brexit and the victory of Donald Trump last year, no one is relying on predictions.

But whether Mr. Wilders’s party wins the most votes, or enters a government, hardly matters. He has already succeeded in one of his main ambitions — to push politics in the Netherlands to the right and make possible a conversation about shutting out immigrants and dismantling the European Union that was unthinkable not long ago.

Mr. Wilders is close ideologically to Marine Le Pen of France, the far-right National Front leader who is set to make it to a runoff in presidential elections this spring. He was also close to Mr. Trump’s campaign, and is sometimes even called the “Dutch Trump,” though he has a far longer political history and as many differences as similarities.

Like Mr. Trump, Mr. Wilders is unafraid to say things in the most direct, divisive, dismissive, and often disparaging and insulting of ways. Similar to Mr. Trump, many of his supporters feel buoyed and relieved that he is giving voice to what they cannot say, or feel they are not supposed to say.

Last week Mr. Wilders delighted in publicly referring to “Moroccan scum” before a gaggle of reporters. He has called the hijab a “useless piece of cloth.” He has been convicted of inciting discrimination and insulting an ethnic group, but was let off without a penalty.

The one time Mr. Wilders was in government, in 2010, he had an informal liaison with the mainstream conservative party’s coalition, but he bolted when it wanted to cut back pension benefits. Those in his parliamentary group are not technically members of his party, allowing Mr. Wilders to entirely control his party’s platform and decision-making.