[6] Kupka became a member of the Civic Democratic Party in 2008 and was elected to the council of Líbeznice with the second highest number of preferential votes among the top three on its candidate list.

[14] During the 2013 Czech parliamentary election, Kupka finished seventh place on the candidate list of the Central Bohemian Region for the Civic Democratic Party.

[25] However, according to the announced results, with 4.87% votes counted and a difference of only 104 left, he was not moved from 31st place to the head of the candidate, thus leaving his potential position as a member of parliament.

[28] In the Chamber of Deputies, he served as vice-chairman of the committee for public administration and regional development with Jakub Janda and Martin Baxa.

[29] In the 2018 Czech presidential election, Kupka defended the position of representative of the municipality of Líbeznice, when he led the ODS candidate.

[35] In the 2021 Czech parliamentary election, Kupka ran as a member of the Civic Democratic Party as the third place candidate of the Spolu coalition in the Central Bohemian Region.

[37] The same year, in November, Kupka became the ODS candidate for the post of Minister of Transport of the Czech Republic in Petr Fiala's cabinet.

[40] This procedure was criticised by the lawyers of the anti-corruption movements Transparency International, Prague-based newspaper Oživení, and MP Martin Kolovratník, who are all referred to by the trade union that has been established in the office.