In 2015 Jan Roos was the campaign leader for GeenPeil, a campaign which got a referendum on the EU-Association Treaty with Ukraine on the books. During this campaign Jan Roos often wore a sailor cap. GeenPeil later ran as a political party in the 2017 general election, but failed to gain enough votes to win any seats in the Dutch parliament. Roos decided to campaign as leader of the VoorNederland party, but also failed to win a single seat.