On Tuesday, he signed a document that paves the way to expanding the U.S. military presence on the island, opening new bases. But it explicitly stops short of conveying any territory to the United States. And no one — especially Denmark, which governs the vast but mostly empty space — wanted to emphasize that point, for fear that Mr. Trump might renounce the agreement he had just hailed as “tremendous for Europe and for the US.” Mikkel Olesen, a researcher at the Danish Institute for International Studies, described the final document, which was released Tuesday, as only a moderate improvement...