dˈʊɹɹɪŋ ðə ɡˈʌvɚnmənt ʌv bᵻlɪsˈæɹɪˌoʊ bˌeɪtəŋkˈɜː, sˈɜːpə wʌz ɪnvˈaɪɾᵻd təbi ɐ nᵻɡˈoʊʃɪˌeɪɾɚ bᵻtwˌiːn ðɪ ˌiːˌɛlˈɛn ɡɛɹˈɪləz ænd wʌz pˈɑːɹt ʌv nˈuːmɚɹəs pˈiːs kəmˈɪʃənz ðæt nˈɛvɚɹ ɐtʃˈiːvd səksˈɛsfəl ɹɪzˈʌlts.
During the government of Belisario Betancur, Serpa was invited to be a negotiator between the ELN guerrillas and was part of numerous peace commissions that never achieved successful results.