Woerden municipal council Den Haan first appeared on the ballot during the
March 2006 municipal election in the town
Woerden. She was placed second on the
party list of
Democrats 66 (D66) and was elected to the municipal council. The following year, she switched to the
Labour Party (PvdA), which cooperates in the Woerden municipal council with
GroenLinks under the name Progressief Woerden. Den Haan was not re-elected in the
2010 elections, being placed seventh on the
party list, but she remained a staffer assisting the group. She was on Progressief Woerden's party list once more in 2014, being their sixteenth candidate.
50PLUS leader and election campaign In July 2020, Den Haan was asked by
50PLUS chair
Jan Nagel to apply for the position of in the
2021 general election. She was not a member of the party. 50PLUS had been without a leader since
Henk Krol had left the party in May to establish the
Party for the Future. The party's leadership put Den Haan forward as their preferred during a press conference in August after fourteen candidates had applied. During an online convention on 3 October, she won the member election with 52% of the 362 votes and thus officially became the party's . Five other people ran for the position including members of parliament
Corrie van Brenk, who received 42% of the vote, and
Léonie Sazias. However, the latter dropped out and endorsed Den Haan to prevent Van Brenk from winning. Before her election, 50PLUS had opposed reforms of the pension system proposed by the cabinet, unions, and employers' associations, but Den Haan had supported them while she was ANBO director. After the election program was released, Den Haan called it a done deal and said that she wanted the party to be involved in working out the details of the reforms. Den Haan also wanted to widen the party's reach by taking care of future elderly people instead of solely defending the interests of the current elderly generation. After the party's third candidate, Ellen Verkoelen, had criticized those comments, Den Haan to no effect called on her to withdraw her candidacy if she disagreed.
House term 50PLUS lost two of its three seats in the 2021 general election, causing Den Haan to become the only member of her party to have a seat in the new House. She was sworn in on 31 March and was on every standing committee including as vice chair of the Committee for Education, Culture and Science. Den Haan announced on 6 May that she had decided to leave 50PLUS due to a falling-out with the party leadership and that she would continue as an
independent politician. The conflict had started during the campaign, and the board had written a letter with numerous complaints about Den Haan's leadership to all 50PLUS members in late April. They accused her of not cooperating with the leadership and of following a progressive course without consultation. Den Haan had in turn reacted in an internal memo that she had been sabotaged, teased, and intimidated. To decrease her workload as an independent politician, Den Haan started cooperating with
Sylvana Simons (
BIJ1) and
Caroline van der Plas (
BBB), who also have a one-person group, while she mostly focussed on elderly policy and income development. However, she told that her idea to pool policy advisors was rejected. In August 2021, she met with the Minister of Tourism and Environment of the unrecognized state of
Northern Cyprus while on holiday. This led to criticism from the
Cypriot Minister of Finance. Den Haan defended herself, saying that she was visiting him informally in her capacity as a private citizen. Later that year, she offered her help to elderly care facilities following personnel shortages due to the
COVID-19 pandemic. After she had received several reactions, Den Haan began volunteering on weekends. She was a member of a committee tasked with the preparation of a
parliamentary inquiry into the government's COVID-19 response and made herself available to participate in the inquiry. When it was indefinitely postponed in June 2022 as only four parties had nominated an
MP to take part, Den Haan co-wrote an opinion piece in which she called it an unwise decision given that the pandemic had impacted all facets of society. She launched her own pensioners' party called
GOUD Netherlands (GOLD, a contraction of 'good old') in September 2022. Den Haan said the party's positions would not deviate much from those of 50PLUS. However, she described GOUD as having a less populist style and being more leftist on issues such as climate and migration. The parliamentary group of 50PLUS in the
Provincial Council of South Holland switched to the new party shortly after. When the
fourth Rutte cabinet collapsed in July 2023 – triggering
a snap election in November – Den Haan announced she would not seek a second term. She called the state of politics ugly, saying populism and opportunism were rampant and that she was suffering from
misogyny. Den Haan joined the board of directors of Zonnehuisgroep
Vlaardingen, a local long-term healthcare provider, in November 2023, where she serves alongside Arjan in 't Veld. == Personal life ==