[7] On 18 September 2018, an agreement was made to promote Maaßen to a role within the Interior Ministry and relieve him of his previous duties once a successor for his post has been agreed on.

[8][1] In April 2021, Maaßen was selected as the Christian Democratic Union's candidate for the constituency of Suhl – Schmalkalden-Meiningen – Hildburghausen – Sonneberg in the 2021 German federal election.

During the 2013 mass surveillance disclosures, German media reported that Maaßen visited the headquarters of the U.S. National Security Agency (NSA) in January and May.

According to classified documents of the German government, Maaßen had agreed to transfer all data collected by the Federal Office for the Protection of the Constitution via XKeyscore to the NSA.

[11] Ob Maaßen Agent des SVR oder FSB ist, kann derzeit nicht belegt werden.

A renegotiation within the government ended on 23 September 2018 with an announcement that Maaßen would now be an "advisor" in the interior ministry, and no longer be receiving a pay rise.

On 5 November, as a result, Interior Minister Horst Seehofer concluded that a trusting relationship with Maaßen was no longer possible, asking president Frank-Walter Steinmeier to place him in early retirement.

The Greens and SPD were both critical of the decision,[18] while CDU official Serap Güler and state minister Karin Prien both expressed outrage.

[20] Maaßen was defeated in the direct mandate election for the Thuringian constituency of Suhl – Schmalkalden-Meiningen – Hildburghausen – Sonneberg by Social Democrat Frank Ullrich.

The 2019 resolution of the presidium and executive committee of the CDU related to the murder of Walter Lübcke indirectly accused Maaßen and the Values Union of complicity: "Anyone who supports the AfD must know that they are poisoning the social climate and brutalizing the political discourse".