[5][6] In 2010, he was chosen by former federal deputy Plínio de Arruda Sampaio to serve as his vice presidential running mate on the PSOL slate that year.

[10] During the vice presidential debate, Assis denounced institutional racism in Brazil and stated that the Pacifying Police Units (UPP) in Rio de Janeiro have brought "terror to the well-being of communities".

[15] According to Jornal A Tarde, Assis and PSOL were harmed in the election by only pledging to take individual contributions, thereby limiting their fundraising ability.

[13] While Assis lost, his campaign in 2012 coincided with the election of the first-ever PSOL alderman on the City Council of Salvador, Hilton Coelho.

[17] During his senatorial campaign, Assis endorsed abortion legalization, the decriminalization of some drugs, the creation of a unicameral federal legislature, and the public financing of elections.

Additionally, he endorsed quotas for Afro-Brazilians to advance racial equality and opposed lowering the age of criminal responsibility.

[23][1] Assis criticized the party's leadership for perceived unfair treatment in favor of Boulos at the expense of internal democracy, and stated that PSOL should be built "from scratch" to keep it in touch with social movements.