After a power struggle for Legionary leadership between Sima and a splinter group led by Vasile Noveanu that had formed while in exile, Sima was brought in by the short-lived Gheorghe Tătărescu government to serve as state secretary within the Ministry of Education. He occupied this position for only six days, and the Tătărescu government resigned on 3 July. On 4 July 1940, he joined the cabinet of Ion Gigurtu as the undersecretary of state in the Ministry of Public Education, as well as Minister of Religion and Arts, alongside two other Iron Guard members. Though Sima resigned from the Gigurtu cabinet after only four days, antisemitism soon became codified in Romanian law, and by 9 August 1940, marriage between ethnic Romanians and Jews was prohibited, as was access to public education for Jewish individuals. Following the secession of Northern Transylvania to Hungary (known as the Second Vienna Award) on 30 August 1940, the Gigurtu government collapsed.