"I am sure that the Colombian people understand that an imperfect peace is preferable to 20 or 30 years of war," he said in an interview published today in Spanish daily El Pais.
The peace deal is due to be signed on September 26 in Cartagena ahead of an October referendum on final ratification of the historic accord with the Revolutionary Armed Forces of Colombia.
Once the deal is formally signed, the FARC, launched in 1964, will have 180 days to demobilise, disarm and relaunch itself as a political party. The UN has agreed to monitor the process.
"I don't understand why my peers in the elite, of which I am part -- I am a member of the poshest clubs in the capital -- have allowed themselves to be misinformed on the advantages of peace.
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"I am sad to see that these people... Don't understand the importance of taking these steps to leave our children a more peaceful country," he said.
He said the accord "will change the history of Colombia."
The conflict, which has drawn in various left- and right-wing armed groups and gangs, has left 260,000 dead, 45,000 missing and 6.9 million uprooted from their homes.