It is this resounding victory that makes the outcome a defeat for Vučić. A parliament without an opposition cannot serve as a fig leaf to legitimize the supposedly democratic rule of the president. Had more of the 21 running parties and groups entered parliament, such as the different far right and fascist groups or a few scattered democratic and reformists, the Progressive Party could claim that Serbia had a pluralist parliament. Now, it does not and thus reveals the authoritarian nature of the regime.
Florian Bieber, Professor of Southeast European History and Politics, Jean Monnet Chair for the Europeanization of Southeastern Europe at the University of Graz and Coordinator of the Balkans in Europe Policy Advisory Group (BiEPAG)

The United States values highly bilateral relations with Serbia, which have improved significantly in recent years. We have a common vision of a democratic Serbia with a prosperous market economy, living in peace with its neighbors and integrated into Europe
Written statement by a State Department spokesperson