While Europe has been busy fretting about Russian meddling in its politics, a few Americans have been quietly doing their part to boost the continent’s far right.

Wealthy American conservatives have poured large sums into the electoral campaign of far-right leader Geert Wilders of the Netherlands’ Dutch Freedom Party, in support of his anti-Islam, anti-EU views.

Three American donors gave €141,668 ($150,430) to Dutch political parties between 2015 and 2017, according to campaign finance documents released this week by the Dutch interior ministry. Two of these donors funded the far-right Dutch Freedom Party.

Americans rarely give money to Dutch political parties, and the sums wouldn’t amount to much in a US election. But as Dutch parliamentary elections approach on March 15, there is concern about the impact of foreign donations in a system heavily reliant on public funding.

The report showed that the PVV had three donors registered since 2015. The largest donor by far was the David Horowitz Freedom Center, a California-based think tank run by right-wing activist David Horowitz, who has called Wilders “the Paul Revere of Europe.” The think tank’s aim is to combat “the efforts of the radical left and its Islamist allies to destroy American values.”

The Center donated just over €108,244 in 2015, the largest individual contribution to a Dutch political party that year. The third donor, J.A. de Keizer, who gave a total €18,700 between 2015 to 2017, was based in Dordrecht.

The foreign support may be waning. According to the latest campaign disclosure report, last year’s contribution by Horowitz to Wilders’ campaign dropped to €22,036. Wilders, who was convicted of hate speech last year, has recently slid in the polls. (Horowitz rallied behind Wilders when he was put on trial and acquitted for inciting hate against Muslims in 2010.)

The PVV is currently projected to win 16% of the vote, or between 24 to 28 seats in the Dutch parliament, down from a prediction of around 20% in January, according to the Dutch Polling Indicator, which combines opinion polls into one estimate. Current prime minister Mark Rutte’s conservative liberal VVD is leading in the polls.

A record 81 parties registered to compete in the Dutch elections, of which 12 may get a spot.

Wilders is running on a one-page manifesto to withdraw all residence permits already granted to asylum seekers, ban all asylum seekers and immigrants from Muslim countries, close all mosques, and leave the European Union. Keen to build on US president Donald Trump’s recent electoral success, Wilders was one of the first European leaders to ape Trump’s infamous slogan.

The third US donor was Chris Rufer, who founded the Morning Star Packing company and serves as president of California Fruit and Tomato Kitchens company. Rufer gave over €4,535 to the small Dutch Libertarian Party, who has yet to win any seats in parliament.