Gustaf Björlin critically examined the decision-making process behind the march across the Belts in 1921. He highlighted the source-critical weaknesses in Dahlbergh's diary and memoirs, which were released long after the course of the depicted events. Dahlbergh had an apparent need to promote his own career and emphasize his exploits in the service of the late king. Later in Dahlbergh's life, he became one of Sweden's most powerful civil servants and military commanders, which, according to Björlin, stimulated his need to polish his early career. Björlin stated that Dahlberg "created his story without any witnesses", since it was not possible to prove the validity of Dahlbergh's reports based on other sources. Later researchers and in subsequent depictions of the campaign, Björlin's examination of Dahlbergh's writings was ignored. It was not until 1948 that Curt Weibull acknowledged Björlin's argument. During his lecture before a Nordic history seminar in Lillehammer, Weibull rejected Dahlbergh's writings, labeling them stories with no factual historical value. Weibull emphasized it was Ulfeldt who played an important role in the king's decision to cross the Belt. Several researchers opposed Weibull, and the debate continued when he returned to the subject in an essay in 1954. Hans Villius, who critically examined Dahlbergh's depiction of the Danish wars in his reports, supported Weibull. In his 1958 book "När Skåne blev svenskt" (), Alf Åberg considered Dahlbergh's stories very unreliable as sources and that he had probably exaggerated his own role in the campaign.