Should states be allowed to secede? Join another country?

Posted by vhu9644@reddit | AskAnAmerican | View on Reddit | 52 comments

An argument I see thrown regarding acquiring Greenland is that Greenlanders should be allowed to decide if they want to become American. As of now, there isn't a legal right for a state to leave the union. Should there be one? Could states decide to join another country? What about for another country to purchase a state?