A closer look at the claim that the Polish State had ceased to exist:
Let's begin with Wikipedia and move on from there.
|The state and international law
By modern practice and the law of international relations, a state's sovereignty is conditional upon the diplomatic recognition of the state's claim to statehood. ...
The legal criteria for statehood are not obvious. Often, the laws are surpassed by political circumstances.
However, one of the documents often quoted on the matter is the Montevideo Convention from 1933
Here is a brief summary of the relevant section of the 1933 "Montevideo Convention on the Rights and Duties of States".
|The state as a person of international law should possess the following qualifications: (a) a permanent population; (b) a defined territory; (c) government; and (d) capacity to enter into relations with the other states.|
The whole text of the Convention is online at the Yale Law School's "Avalon Project" - http://avalon.law.yale.edu/20th_century/intam03.asp It is also at http://www.taiwandocuments.org/montevideo01.htm
According to the corresponding Wikipedia article
as a restatement of customary international law, the Montevideo
Convention merely codified existing legal norms and its principles and therefore does not
apply merely to the signatories, but to all subjects of international law as a whole.[5
- Harris, D.J. (ed) 2004 Cases and Materials on International Law 6th Ed. at p.
99. Sweet and Maxwell, London ]
According to Thomas D. Musgrave, Self-determination and national minorities (Oxford Monographs in International Law, Oxford University Press, 2000) p. 235 n. 170, in 1991 the Badinter Arbitration Committee of the European Union used the following definition of the state:
|In Opinion No. 1 the Commission had noted, at p. 1495, that "the State is commonly defined as a community which consists of a territory and a population subject to an organized political authority; that such a state is characterized by sovereignty.|