 Historically the PRI had been the dominant party in regional politics, until 1989 when the PAN began to dominate the city, until yet again, in 2004, PRI began regaining prominence and won the Mayor's Office.Less prominent parties also maintain relations with the dominant parties.These other parties, with less presence include the New Alliance Party (PANAL), Social Encounter Party (PES), and Party of the Democratic Revolution (PRD).