A founding member of PT, Greenhalgh was affiliated 1974–1980 to the Brazilian Democratic Movement (MDB), the party that previously represented the civilian opposition to the dictatorship. He was federal deputy for São Paulo and vice mayor of São Paulo in the government of Luiza Erundina (1989–1993).Analysis: Will 21st century belong to Brazil? by CARMEN J. GENTILE, (UPI) on Feb. 1, 2005 He participated in the creation of a special committee, the Brazilian Committee of Solidarity with the Peoples of Latin America in 1980.The São Paulo Forum, Castro's shocktroops published in November 10, 1995 issue of Executive Intelligence Review
