Casas has been a local deputy for the La Rioja Province from 2005 to 2011. He served as vice-governor from 2011 to 2015, under Luis Beder Herrera. He won the primary elections in the localJusticialist Party to run as governor, defeating the ministers Javier Tineo and Néstor Bosetti; Bosetti would run as his candidate for vicegovernor. He was elected governor in 2015 with the 53% of the vote. The candidate of the Radical Civic Union denounced electoral fraud, but eventually accepted Casas' victory. The province allows for a re-election, but as he served as vice-governor and governor in two consecutive terms, he may not run again in 2019. He acknowledges both the former governor Beder Herrera and the former president Cristina Fernández de Kirchner as political leaders. Casas attended the presidential inauguration of Mauricio Macri on December 10, 2015, despite of the instructions from the Front for Victory to avoid doing so. He then returned to La Rioja, to take office as governor. He had a personal meeting with Macri shortly after they took office, and they talked about the problems of the province. They agreed in the need to improve the infrastructure of the province. In contrast with Beder Herrera, Casas received the local mayors and legislators of other political parties, to arrange joint actions on behalf of the province. He announced that he would promote the production of tomatoes. He made an amendment to the constitution of La Rioja, to be able to run for a new term in 2019. It was followed by a referendum: only 43.95% of the registered voters attended it, and of those 25.27% supported the amendment and 17.90% rejected it. However, the local parties do not agree on the interpretation of the results. Cambiemos, the main opposition party, considers that Casas should have obtained 35% of the vote to approve the amendment, and Casas considers that it is instead the explicitrejection the one that should have achieved such 35%. As a result, they do not agree if the amendment should be in force or not.
