the pwersa ng masang pilipino (pmp), headed by former president joseph estrada, and the partido demokratiko pilipino-lakas ng bayan (pdp-laban), headed by vice president jejomar binay, signed a coalition agreement on april 4, 2012 for the 2013 elections, forming the united nationalist alliance (una). the two parties had been partners in the united opposition in the 2007 election, and estrada and binay were running mates during the 2010 presidential election. aquilino pimentel iii, pdp-laban president, has stated that the una's senatorial slate is now more than twelve members and is being trimmed down; he had also expressed reservations on the inclusion of juan miguel zubiri, of whom he had won an election protest after the 2007 election. on march 2014, binay resign as chairman of pdp-laban, as result the pmp party the only primary party of una banner.