Nationalism was clearly the motivation behind some of the Atlantis theories that have been proposed over recent centuries. Olaf Rudbeck audaciously promoted his native Sweden in the 17th century, just as the eccentric William Comyns Beaumont claimed that Britain was Atlantis in the early 20th century and some Albanians, Azoreans, Maltese and Sardinians make comparable claims today. However, the most sinister manifestation of Atlantis based nationalism was the attempt to hijack it as the original homeland of the Aryan predecessors of the Nazis, probably borrowing the idea from Blavatsky. This was partly to replace the Abrahamic cultural lineage claimed by so many western nations. Today elements of modern Russian nationalism also look to an Aryan ancestry based in the Arctic.
*The linking of nationalism with (pseudo)archaeology is exemplified by the Bosnian pyramid claims of Samir Osmanagich and the manner in which the local media and politicians have used them to boost national pride, in spite of the contrary views expressed by qualified geologists and archaeologists(b).*
Vanessa Ward gives a good overview of the Atlantis based nationalism of both Rudbeck and the Nazis(a).