He was an early supporter of Antonio Cafiero's Peronist Renewal faction within the Justicialist Party, and was elected to the Argentine Chamber of Deputies for the City of Buenos Aires in 1985.

His party list lost the 1997 congressional primaries to Daniel Scioli's, however, who enjoyed the support of President Carlos Menem,[3] and Toma consequently left Congress.

[4] Amid political crisis of December 2001, Toma was appointed Minister of Justice, Interior, Defense and Human Rights, holding all roles concurrently for just 48 hours.

He was appointed by then President Eduardo Duhalde to replace the previous Secretary, Carlos Soria, following the assassination of two left-wing agitators in Avellaneda.

[6] During his tenure, the final report on the AMIA bombing was published to the judicial branch and foreign intelligence services, but would remain classified to the general public.