Pim Fortuyn List Eerdmans first joined the Christian Democratic Appeal but left after disagreeing the CDA's course and saying in his own words "I thought they spoke a different language. I started to dislike it more and more." A week after leaving the
Liveable Netherlands party in 2002, Eerdmans contacted
Pim Fortuyn, who at that time was busy assembling a list of candidates for his new political party, the
Pim Fortuyn List (LPF). Eerdmans was placed nineteenth on the list and after the
2002 election he became a member of the
House of Representatives, while his party joined the
First Balkenende cabinet. Eerdmans focused on matters related to justice and police. Together with then
PvdA MP
Aleid Wolfsen, he submitted a bill to punish animal cruelty more severely and argued for increasing minimum sentencing for violent crimes. In 2005, Eerdmans was awarded the
Thorbecke Prize from
Leiden University which is awarded to the "most eloquent politician." After the fall of the cabinet,
new elections were called. This time the LPF won only eight seats, but since Eerdmans was second on the list he remained in Parliament. He was removed from the party's parliamentary faction after it was definitively announced that Eerdmans would be on the One NL candidate list for the
2006 election.
One NL For the 2006 general election, Eerdmans split with the LPF to form a new political party called
One NL with
Marco Pastors of
Leefbaar Rotterdam. After the dismal result of One NL in the 2006 election, Eerdmans left Dutch politics and worked in business before forging a career as a television and radio broadcaster.
Leefbaar Rotterdam Eerdmans made a return to local politics when he was elected
lijsttrekker of Leefbaar Rotterdam on 6 October 2013. In the
local elections of 2014 Leefbaar Rotterdam became the biggest party in Rotterdam, meaning the party would get the chance to lead the formation of a new coalition. The party subsequently formed a coalition with the
Democrats 66 (D66) and
Christian Democratic Appeal (CDA), in which Eerdmans became an
alderman.
Forum for Democracy Eerdmans worked with the
Forum for Democracy during the
2018 Dutch municipal elections. For the
2021 general election, Eerdmans announced a return to national politics and was to be fourth on the party list of FvD led by
Thierry Baudet. However, before this could be effectuated Eerdmans quit the party soon after the announcement, citing what he saw as the FvD's insufficient handling of antisemitism, homophobia and racism scandals from other party members.
JA21 After leaving the Forum for Democracy, Joost Eerdmans founded a new political party,
JA21 (Right Answer 2021), together with other former FvD members to contest the 2021 general election. Eerdmans stated that he sought to revive
Fortuynism in Dutch politics and said JA21 would follow the original founding ideas of the FvD. He described JA21 as a "a broad people's party on the right" and a "common sense" right-wing party positioned to attract voters who considered the VVD too centrist, the PVV too harsh in tone, and the Forum for Democracy as having become directionless. Eerdmans became the party’s leader and
lijsttrekker. In the 2021 election, JA21 won three seats in the House of Representatives, returning Eerdmans to the House of Representatives for the first time since 2006. During the
2023 Dutch general election JA21 fell to one seat with Eerdmans being the only JA21 MP to return. In September 2024, the House passed a motion by Eerdmans and
Chris Stoffer (
SGP) to prohibit face coverings during protests, intended to aid police in identifying individuals committing offenses, citing the
2024 pro-Palestinian protests on university campuses in the Netherlands as an example. The House later approved another motion by Eerdmans requesting that the government revoke the
charitable status of the environmental group
Extinction Rebellion, arguing that the organization’s activities were unlawful and disruptive. When the
Schoof cabinet introduced its
2025 budget proposal, which included €2 billion in education cuts, Eerdmans collaborated with other centrist and conservative opposition parties in what he referred to as an "
unholy alliance". In December 2024, the coalition agreed to reverse €750 million of the planned cuts to secure
Senate support. Eerdmans declined to endorse the revised budget. JA21 saw its strongest result to date during the
2025 Dutch general election. ==Political beliefs==