Trigger Strategies

Two neighboring countries are engaged in deciding whether to maintain open borders to allow free movement of goods between them or to erect trade barriers every year. This scenario is structured as an infinitely repeated game where both countries are guided by the same discount factor. What is the minimum discount factor where both countries keep their borders open until one of them erects a trade barrier, prompting the other to erect barriers indefinitely, resulting in a subgame perfect Nash equilibrium. The profits for both countries keeping their borders open are both cooperate, for the country maintaining open borders while the other erects barriers are cooperate, defect respectively, and for both countries erecting barriers, the profits are both defect. Round your answer to two decimal places.