Later, Paz studied at the American University in Washington, D.C., where he graduated with a bachelor's degree in international relations with a major in economics and a master's in political management.

[1] During the presidency of Hugo Banzer —whose government was supported by the MIR— he worked as a commercial attaché at the Bolivian embassy in Spain and served as chargé d'affaires to the World Trade Organization.

In the 2002 general elections, the MIR nominated Paz as its candidate for Tarija in circumscription 49 (Avilés-Méndez), a major stronghold of support for the party.

[2][3] Though the significant social conflicts of the time culminated in the collapse of the traditional party system, Paz's already-established political career survived.

When the legislature's mandate was shortened by two years, he was presented by a diminished MIR as its candidate for Tarija in circumscription 46 (Cercado) for the 2005 general elections, in alliance with Social Democratic Power of Jorge Quiroga.

[4][5] By 2006, the inability of the MIR to achieve the required two percent vote threshold in that year's constituent assembly elections led to the loss of its national registration.

Failing the creation of IDEs due to a lack of time to establish such institutions, Paz also proposed the formation of inter-institutional monitoring committees made up of governorates, municipalities, universities, regional chambers, social organizations, and other relevant groups to guarantee transparency in the process.