i get the impression that what greenland wants is independence from denmark and a compact of free association with the us, like the marshall islands have. mi (officially rmi, republic of the marshall islands) is an independent and sovereign state that, thanks to its agreement with the us, has a us post office and protection from the us military. greenland would likely enjoy us protection (from china and russia), independence in its internal affairs, and a revenue-sharing agreement with the us regarding resources discovered there to pay for us protection.
United States