House of Representatives (2020–2021)

Terpstra ran for House member during the 2017 general election. During the campaign, he said that abolishing the student loan system was his priority.^[20] He was placed 23rd on the CDA's party list and received 1,477 preferential votes.^[21] His party won nineteen seats, resulting in Terpstra not being elected. After Erik Ronnes had vacated his seat to join North Brabant's provincial-executive, Terpstra was sworn in as MP on 20 May 2020.^[6] Terpstra became the CDA's spokesperson in the area of housing, spatial planning, and the Environment and Planning Act.^[22] In the House, he was a member of the Committee for the Interior.^[23]

He has advocated for addressing the Dutch housing shortage and for reducing difficulties that young people face when trying to buy their first house. In July 2020, Terpstra introduced a motion, which was approved unanimously by the House, calling for the consideration of previous rent payments when applying for a mortgage. This would make it easier to get financing for a house for people who have already been paying rent at a higher or similar level as the mortgage would be.^[24] He has also unsuccessfully called for the interior minister to force Utrecht to build 25,000–30,000 homes in the polders Rijnenburg and Reijerscop.^[25] A motion by Terpstra and Daniel Koerhuis was narrowly passed by the House.^[26]

Terpstra was the 20th candidate of the CDA during the 2021 general election.^[27] He was not re-elected, as his party won fifteen seats. Terpstra personally received 1,297 votes.^[28]

Leiden alderman (since 2022)

Following his membership of the House, Terpstra started working for construction firm Heijmans in July 2021. He was the CDA's lead candidate in the March 2022 Dutch municipal election in Leiden.^[1][29] The local campaign was notable for humorously distancing itself from the national party. Its website stated that voters might think twice about voting for the CDA nationally, but that the local party is allowed to be different due to the lack of Kim Jung Hoekstra practices, combining the names of party leader Wopke Hoekstra and North Korean dictator Kim Jong-un.^[30] The CDA lost one of its three seats – following national polling trends – and Terpstra was sworn into the council on 30 March.^[31][32][33] The CDA joined Leiden's new governing coalition as its only non-leftist member party. Terpstra represented his party in the municipal executive as alderman responsible for housing, construction, and welfare.^[34] His term started on 16 June, having stepped down as councilor two days before.^[35][36] That same month, investigative journalism platform Follow the Money wrote that sites Terpstra and Koerhuis had promoted for housing developments as members of parliament were partially owned by major property developers. Terpstra subsequently denied having had ties with developers.^[37] In August 2023, Terpstra proposed to the municipal council to bar investors from buying houses in Leiden worth less than €355,000 in order to reduce competition on the housing market. Additionally, he suggested restricting the splitting of houses into student residences as well as mandating that landlords apply for a permit in certain neighborhoods to ensure good renting practices.^[38]

Terpstra was offered a seat in the House of Representatives following the resignation of Raymond Knops in February 2023. He declined it to stay on as alderman.^[39]