As a member of this group, he defended the limits of Peru questioned by Ecuador as ambassador on a special mission to Spain, Germany and Italy.

[1] As a student at the Catholic University, he participated in demonstrations, demanding the legality of political parties, as well as free and democratic elections.

In various interviews, Valle Riestra commented that on the outward journey he spoke with the son of former Bolivian president Enrique Peñaranda, who recommended that he go into exile in Madrid.

For the 1985 elections, Valle Riestra announced his candidacy for APRA nomination for President, but he withdrew after it was evident that he would lose to victor Alan García.

In the 1990 election, he was the second running mate of APRA nominee Luis Alva Castro but the ticket lost to Alberto Fujimori.

In 1998, President Alberto Fujimori offered him the office of the Prime Minister of Peru, a post he assumed for a short time.

His tenure in office cost him his disagreements with some members of the Peruvian Aprista Party, who totally disapproved of the Fujimori regime.