I've collected some information about the issue from the autobiographies of a few of the people involved.
Lennart Bernadotte - His father, Prince Wilhelm, spoke to King Gustav V and his uncle Prince Carl & Princess Ingeborg. The former was resigned, but reluctantly supportive and the latter friendly and supportive. Then during Christmas the future Gustav VI Adolf spent hours trying to persuade Lennart not to go through with the marriage citing the financial repercussions it would have and badmouthing the Nissvandt family and the morals of Karin. It's worth adding that in spite of what he said that although not rich the Nissvandts were a perfectly respectable upper-middle class family and one of Karin's sisters had married a count Mörner. After that Gustav V had a talk to him where he repeated the claims of his son and spoke about his duties to king, country and the monarchy. This went on until Lennart took the statues of the Royal Hunting Club and showed his grandfather that Karin's father was not only a member, but had also signed that year's account rapport (?). After that the king dismissed him with a kiss and never spoke ill off the family again. He even invited Lennart to accompany him in the Royal box at the Opera the day after the engagement had been formally announced. Lennart writes that Carl & Ingeborg later told him that "someone" had fed his uncle and grandfather false information.
Sigvard Bernadotte - mentions a romance with a girl called Marianne. Sister of a friend from school so from a privileged background. When he told his father that he wanted to marry her he basically got the same story about her and her family that Lennart had got about Karin and the Nissvandts. Sigvard capitulated that time, but years later had it all repeated when he wanted to marry Erica Patzek. He had the same talk with his grandfather about his duties to Sweden and the monarchy as Lennart but wasn't dismissed with a kiss but with a "you silly boy". He was contacted by an onslaught of family members, officials friends etc who all tried to persuade him to marry Erica. After the marriage not only was his appanage stopped, but he had his bank account blocked so he couldn't access his money.
Kerstin Bernadotte - the divorced journalist from a poor, yet respectable and well-connected middle class family calls what she went through a cold war after her relationship to Prince Carl Johan became public knowledge. She was subjected to a campaign led by the Court Marshall to blacken the reputation of her and her family, she was called up to the Marshall of the Realm who tried to persuade her to give up on Carl Johan. He called her a fortune hunter and later spread rumours about her being an alcoholic. Before a work trip to Hungary in 1943 she found that her passport had been "forgotten" in the office of Torsten Nothin, the Governor of Stockholm, and only through pulling every string available did she get her passport on time. Nothin later wrote in his memoirs about how the court tried to have her passport invalidated in 1945 when she was about to travel to USA to marry Carl Johan. On may 25 the governor posted his formal refusal to break the law to the court and to the King personally. There were also formal attempts to get the American authorities not to give Kerstin a visa which delayed the wedding a few months. When the engagement was finally announced Carl Johan was called up to a resigned King Gustav V who dismissed his grandson with an offer of some cigarettes. He then said "this is the last thing that you'll ever get from me". Kerstin writes that there was never a formal break between Carl Johan and his father although relations were tense for many years. Like her sister-in-law Marianne she later developed a deep and affectionate relationship with her father-in-law. She also writes that both him and Queen Louise several times during the 50s and 60s said how blind and wrong they had been.
A long and messy post, but I hope it gives some insight into the experiences of some of those involved in the Bernadotte marriage saga.
Thank you for answering my question so extensively and for using information directly from the principal parties!
I see, the "war" against the (upper-)middle-class wives and their families was carried out mainly before the marriage in an effort to stave off the prospective marriages.
So, the King and Crown Prince appealed to the princes' duty to the monarchy along with the dangers of marrying into families with allegedly checkered reputations. I wonder which was the greater contributing factor to Gustaf V and Gustaf VI Adolf's own opposition to the marriages. With the King initially resigning himself to the first unequal marriage of the generation (Lennart's) before changing course and attempting to block it, I will speculate that perhaps he could reconcile himself to one out of many princes removing himself from the royal line under the 1810 Act of Succession, but had second thoughts when he realized the potential domino effect of prince after prince being lost to the monarchy. As for the sleaze accusations, the explanation of "someone had fed his uncle and grandfather false information" seems a bit farfetched if the same sort of charges were leveled against every fiancée.
It's interesting that with its political authority already significantly diminished by the middle of the 20th century the monarchy hung onto enough influence to block or nearly block bank accounts and travel documents. One wonders how much of that hidden clout still survives.
As both Lennart and Sigvard writes it was all part of attempts to dissuade other princes from jumping ship. The one who suffered the most was Sigvard who was shunned from the family for years. Lennart and Carl both had the support of their parents and according to Kerstin there was never a complete private break between Carl Johan and his father so even rigid Gustav Adolf seems to have mellowed as the years passed. A passage in Sigvard's memoirs mentions Lennart celebrating Christmas with the Royal family as early as two years after his marriage. WWII led to both princes returning to Stockholm and after that they both became natural parts of the Royal family again. By the 50s all the princes had both been re-embraced by the family and at the instigation of the King Gustav VI Adolf been given comital titles by Grand Duchess Charlotte of Luxembourg. Kerstin and Marianne writes that "Gusty" and "Ist" became devoted grandparents and step-grandparents to their children.
That said, in spite of the family mending the former princes were shocked when the will of Gustav VI Adolf was opened and it was revealed that the most significant part of his estate had been left to Carl XVI Gustav, Princess Christina, Princess Birgitta and Prince Bertil of whom the latter two had agreed to sacrifice their personal lives to support the monarchy.
I do understand why the ex-princes may have expected that the reconciliation, or compensation for their suffering, should have earned them a more equal share of the inheritance. But to me it does seem reasonable and in the interest of fairness and the monarchy to reward the family members who voluntarily made the greatest sacrifices.
All of this also causes me to wonder how much all of this family history may have been responsible for Carl XVI Gustaf's pattern of bending traditions and laws, where possible, to maximize the number of spare workers and spare heirs, though I should probably move that thought to a more suitable thread.
(Incidentally, I think you meant to write that "Christina and Bertil" and not "the latter two [Birgitta and Bertil]" had agreed to sacrifice their personal lives to support the monarchy, and that "an onslaught of family members, officials friends etc who all tried to persuade him
not to marry Erica", is that correct?)
