My dear P.M.,
Again on the subject of the Duke of York and the possibility of his being allowed by the King to take a Governor-Generalship in one of the Dominions.
I have it on the best authority that, prior to the last Imperial Conference, the King, whilst being in favour of Royal Tours, was opposed in principle to the Royal Princes acting as Governors- General, because (a) he did not think that any of them had sufficient experience or knowledge of the world, and (b) there was the possibility of their being embroiled in political controversy of the type of Lord Byng's constitutional trouble in Canada of two years ago. 
However, since then the Duke of York has successfully conducted his tour to Australia and elsewhere and has, I am told, in the eyes of his advisers at least, reaped something approaching sufficient benefit and experience therefrom to warrant his holding a Governor-Generalship. Also the 1926 Imperial Conference has altered the status of Governors-General to that of personal representatives of the Crown, which presumably removes them from any possibility of engaging in political or constitutional controversy.
But even if, as is possible, the King's personal objections are removed, there is still the fact that the Duchess of York has come to be relied on to a great extent to relieve the Queen of a number of her social and philanthropic obligations, there being no other appropriate Royal Lady to whom these can be delegated.
Then there is the question of further additions to the Duke of York's family, which are quite possible, and, of course, most desirable in the absence of any other male heir.
The gist of the above came out in' confidential conversation with Hodgson , Private Secretary to the Duke of York.
It is clear that unless and until the Prince of Wales marries, there will be objections to the Duke and Duchess going to a Dominion.
However, in any event, there is no doubt that if a Dominion definitely asked for the Duke of York as its Governor-General, the King would find considerable difficulty in giving adequate reasons for refusing.
Now, with regard to the Prince of Wales. As far as I can gather the efforts to bring pressure to bear on him with regard to his marriage have had no result. He is, I believe, opposed to marrying a commoner, and a good many of the foreign princesses are impossible from the point of view of their religion. There are two, however, who might be eligible and possible and who, presumably, are considered-Princess Ingrid of Sweden, and the daughter of Princess Andrew of Greece.
The failure of all previous efforts to convince the Prince of Wales of the urgent necessity of his marrying has brought one responsible and well-informed friend of mine to suggest that you, as Prime Minister of one of the major Dominions, are the person to talk to him on the subject, when you are in London at the 1929 Imperial Conference.  He came to this way of thinking through the logical and reasonable argument that the Royal Family is the one remaining Imperial link, and that their continued high prestige and the certainty of the succession in a straight line is no less than essential for the maintenance of the Empire. For certain reasons you are more a suitable person than Mackenzie King to address him on this subject.
You may say that this is Mr. Baldwin's  pigeon. Well, the only polite answer that I have to that is that he apparently hasn't had much success in the matter.
I am, Yours sincerely, R. G. CASEY