What they have falls short of a defense pact. The "Treaty of Good-Neighborliness" contains language that the countries shall immediately discuss military options when under attack, but an agreement to talk is not an agreement to join a war.
This is what article 9 says: "When a situation arises in which one of the contracting parties deems that peace is being threatened and undermined or its security interests are involved or when it is confronted with the threat of aggression, the contracting parties shall immediately hold contacts and consultations in order to eliminate such threats."