[1] He eventually became assistant secretary in the Chrysler Corporation's public procurement division, responsible for dealing with the United States Department of Defense.

[1] Although now beginning to be established in the United States, Donaldson took a keen interest in the developing political movement for Scottish independence back home.

In 1932, Donaldson married Violet "Vi" Bruce, another expatriate Scot (from Forfar) and they set up home in Washington D.C., where he continued to work for Chrysler.

Donaldson joined the Scottish National Party (SNP) in 1934, and three years later returned to his native Scotland with his family, settling at Lugton, Ayrshire, where he established a poultry farm.

[citation needed] In May 1941, during the Second World War, Donaldson's home was raided by the police, who suspected him and a number of other SNP figures of "subversive activities", due to their support for the Scottish Neutrality League.

An MI5 file, published in 2005, outlined how Donaldson had revealed to a close confidant - who was also a British agent - that a network of Nazi sympathisers was planning to undermine the war effort.

[citation needed] MacCormick had left the SNP in 1942, as he had been unable to persuade the party to adopt a position of supporting devolution rather than independence, a split which Donaldson himself had put down more to a personality clash than to ideological differences.

[1] This success, however, did not leave Donaldson without his critics, and at the 1967 SNP Annual Conference he faced a leadership challenge from Douglas Drysdale, which he comfortably defeated.