Section 2.
between Citizens of different States,—between Citizens of the same State claiming Lands under Grants of different States, and between a State, or the Citizens thereof, and foreign States, Citizens or Subjects.
Look again. It also states ". . . trial shall be held in the state where the said crimes shall have been committed; but when not committed within any state, the trial shall be at such place or places as the Congress may by law have directed." The jurisdiction has to be within the power of that court to compell enforcement, to reach out and incarcerate the at fault party, to jail, or seize their properties, or in someway make the injured party whole. Otherwise, nope.
There is absolutely no way that the sovereign government of Croatia of pre-WW II is within the jurisdiction of the US Courts. In fact, these injuries may be res judicata due to the treaties signed after WWII. . . and the general rule of law is that the case dies with the plaintiff or are you arguing that any of the injured parties and witnesses of those events from the period are still alive and kicking? There can only be hearsay evidence at this point, 85 years after the fact. The last survivor of Pearl Harbor 1941 is 105. In addition, what laws in what jurisdiction of the US were broken that it can be tried here? What jury of peers can truthfully be empaneled to hear this? None. There are no peers alive today. The peers of the people who are accused of doing this are all dead or are so old their faculties are questionable.