It seems to me we have wandered rather far afield from the original topic of this thread, and that indeed this ground has been well plowed before, but perhaps that was on the old Forum. Nonetheless, I can't resist adding an observation or two.
Specifically, with regard to the notion that Britain gave Poland a "blank check", I would suggest that a reading of both Chamberlain's March 31, 1939 speech to the House of Commons and the final Agreement of August 25, 1939 clearly show that Britain left itself an escape hatch. They can be found in the British Blue Book at:
Here is the text of Chamberlain's speech:
The Prime Minister (Mr. Chamberlain): The right hon. gentleman the leader of the Opposition asked me this morning whether I could make a statement as to the European situation. As I said this morning, His Majesty's Government have no official confirmation of the rumours of any projected attack on Poland and they must not, therefore, be taken as accepting them as true.
I am glad to take this opportunity of stating again the general policy of His Majesty's Government. They have constantly advocated the adjustment, by way of free negotiation between the parties concerned, of any differences that may arise between them. They consider that this is the natural and proper course where differences exist. In their opinion there should be no question incapable of solution by peaceful means, and they would see no justification for the substitution of force or threats of force for the method of negotiation.
As the House is aware, certain consultations are now proceeding with other Governments. In order to make perfectly clear the position of His Majesty's Government in the meantime before those consultations are concluded, I now have to inform the House that during that period, in the event of any action which clearly threatened Polish independence, and [my emphasis] which the Polish Government accordingly considered it vital to resist with their national forces, His Majesty's Government would feel themselves bound at once to lend the Polish Government all support in their power. They have given the Polish Government an assurance to this effect.
I may add that the French Government have authorised me to make it plain that they stand in the same position in this matter as do His Majesty's Government.
Here is the relevant portion of the Anglo-Polish Agreement:
Agreement of Mutual Assistance between the United Kingdom and Poland.-London, August 25, 1939.
Should one of the Contracting Parties become engaged in hostilities with a European Power in consequence of aggression by the latter against that Contracting Party, the other Contracting Party will at once give the Contracting Party engaged in hostilities all the support and assistance in its power.
(1) The provisions of Article I will also apply in the event of any action by a European Power which clearly threatened, directly or indirectly, the independence of one of the Contracting Parties, and was of such a nature that the Party in question considered it vital to resist it with its armed forces.
(2) Should one of the Contracting Parties become engaged in hostilities with a European Power in consequence of action by that Power which threatened the independence or neutrality of another European State in such a way as to constitute a clear menace to the security of that Contracting Party, the provisions of Article I will apply, without prejudice, however, to the rights of the other European State concerned.
Should a European Power attempt to undermine the independence of one of the Contracting Parties by processes of economic penetration or in any other way, the Contracting Parties will support each other in resistance to such attempts. Should the European Power concerned thereupon embark on hostilities against one of the Contracting Parties, the provisions of Article I will apply. [my emphasis added]
Neither the speech not the Treaty left British intervention solely up to the whim of the Polish Colonels' Junta. That intervention depended on the fulfilment of two
conditions: an action (a) which clearly threatened Polish independence, and (b) which Poland considered vital to resist by force of arms. Even though Poland should decide to take up arms, Britain could obviously take the position that no clear threat to Polish independence was involved and that the Treaty was therefore inapplicable.
Moreover, the emphasis on Britain overlooks the fact that France already had mutual assistance Treaties with Poland dating back to 1921 and 1925. These can be found in full text in the French Yellow Book at the Avalon web sit indicated above. Here are relevant portions of the 1921 Treaty:
Franco-Polish Agreement (this agreement was supplemented by a military agreement regarding its execution signed on the same day) concluded in Paris, February 19, 1921
THE Polish Government and the French Government, both desirous of safeguarding, by the maintenance of the treaties which both have signed or which may in future be recognized by both parties, the peace of Europe, the security of their territories, and their common political and economic interests, have agreed as follows:
3. If, notwithstanding the sincerely peaceful views and intentions of the two contracting States, either or both of them should be attacked without giving provocation, the two Governments shall take concerted measures for the defence of their territory and the protection of their legitimate interests within the limits specified in the preamble.
Here are relevant portions of the 1925 Treaty:
Treaty of Locarno Between France and Poland
(October 16, 1925)
THE President of the French Republic and the President of the Republic of Poland,
Equally desirous to see Europe spared from war by a sincere observance of the undertakings arrived at this day with a view to the maintenance of general peace:
Have resolved to guarantee their benefits to each other reciprocally by a treaty concluded within the framework of the Covenant of the League of Nations and of the Treaties existing between them;
And have, to this effect, nominated for their plenipotentiaries,
Who, after having exchanged their full powers, found in good and due form, have agreed on the following provisions:
In the event of Poland or France suffering from a failure to observe undertakings arrived at this day between them and Germany, with a view to the maintenance of general peace, France and, reciprocally, Poland, acting in application of Article 16 of the Covenant of the League of Nations, undertake to lend each other immediate aid and assistance, if such a failure is accompanied by an unprovoked recourse to arms.
In the event of the Council of the League of Nations, when dealing with a question brought before it in accordance with the said undertakings, being unable to succeed in securing the acceptance of its report by all its members other than the representatives of the parties to the dispute, and in the event of Poland or France being attacked without provocation, France, or reciprocally Poland, acting in application of Article 15, paragraph 7, of the Covenant of the League of Nations, will immediately lend aid and assistance.
As to Richard Overy's notion, endorsed by Michael Mills, that:
If Hitler were to be confronted militarily, while Britain and France maintained economic stability and domestic political peace, then 1939 was in some respects the best time to do so. Allied rearmament was planned to peak in 1939/40, while the advantage of using up unemployed resources and avoiding inflation was not expected to last beyond the winter of 1939.
the British Chiefs of Staff were certainly not of that opinion. In a thoroughly pessimistic study entitled "European Appreciation" for the years 1939/1940 which they produced in February 1939, they evaluated Britain's prospects for success in the event of a global war and found them very poor. See Donald Cameron Watt How War Came: The Immediate Origins of the Second World War
Pantheon Books, 1989) at 165. According to Lord Beaverbrook, "the guarantee to Poland had been given against the advise of the General Staff, who declared that they were not capable, with the resources we had, of fulfilling the committments we had thereby undertaken." Chamberlain refused to permit the General Staff's view to be circulated to the full Cabinet, on the grounds that it would be "tantamount to a criticism of his policy." Leonard Mosely On Borrowed Time: How World War II Began
(Random House 1969) at 207, citing B.H. Liddell Hart.
I still am of the view that the British, and particulary Chamberlain, were highly incensed by Hitler's take-over of the remains of Czechoslovakia and finally persuaded that he was an incorrigible liar and cheat, that his most solemn word was not to be trusted, and that his ambitions were to achieve hegemony over all of Eastern Europe by whatever means it took. It seems to me that the purpose of the "guarantee" to Poland was to give Hitler fair and clear warning of its intent (which Britain had been highly criticized for failing to do as WW I approached) to go to war if Hitler chose military means to acheive his ends, and to bolster France's backbone in living up to her own Treaties with Poland - all in the hope of detering Hitler from gambling that the Allied powers would once again stand aside in the threat of general war.