Colombia's motivation is obvious: Colombians didn't like the court's ruling last week expanding (from Colombia's perspective) Nicaragua's maritime sovereignty in the Caribbean at Colombia's expense.
But the ruling leaves Colombia with one less international legal mechanism to peacefully resolve disputes between members and erodes Colombia's authority in every international organization. The pact, signed in 1948, is formally named The American Treaty for Peaceful Solutions, and it appears to have worked. As far as I know, there's never been a war between two nations which had ratified the pact. (Peru and Ecuador fought their border wars before Ecuador's 2008 ratification.) Previous to the pact, however, Latin American nations fought numerous border wars, including the ones which dismembered Paraguay and Bolivia and the 1932 Peru-Colombia war over Leticia.
Several border disputes, including ones between Chile and Argentina, Chile, Bolivia and Peru and another between Colombia and Venezuela over their border in La Guajira - which brought them close to war in 1987 - still fester in the region. The Bogotá Pact provides a presumably objective authority to resolve those peacefully, if not to everybody's liking.
By withdrawing from the Pact, Colombia rejects the authority of that court. But its decision comes too late juridically. After all, at the time the court ruled last week, Colombia was still a member of the pact and recognized the court's authority. And the Colombian government should also remember that, along with expanding Nicaragua's waters, the court also reaffirmed Colombia's sovereignety over the San Andres islands and their surrounding keys - which was what Colombia had asked for in the first place. By rejecting the new maritime boundary, Colombia also delegitimizes the ruling on the islands and keys.
Nicaragua has said it is sending military ships to patrol the waters which it now considers its territory. But Colombia says it is maintaing warships in the region. Does this sound like a threat of war?
Colombia's decision to leave the Bogotá Pact, like a child who abandons a game because he didn't win all he wanted, will also delegitimize Colombia in all international organizations, because other nations will suspect that Colombia, if it doesn't get its way, will simply abandon the field.
Colombia's decision, "means not only a violation of an international norm, but also confronts Colombia against the United Nations system and the international community," Walter Arévalo, professor of international relations at the Universidad del Rosario, said in an analysis published on the Congreso Visible website.
That's not a good position for a nation like Colombia, which has relied heavily on international cooperation, to be in.
By Mike Ceaser, of Bogotá Bike Tours