After obtaining a Masters in economic history at the University of Gothenburg (Sweden) in 1981, Tunander wrote for philosophical magazines and in 1985 he published two books in Swedish.

While finalizing his doctoral thesis Cold Water Politics (1989) on US Maritime Strategy, technology, and the geopolitics of the North, he received a research position at PRIO in Oslo.

[4] He headed a Nordic study group, "A new Europe", from mid-1980s with Ole Wæver, Iver B. Neumann, Sverre Jervell, and Espen Barth Eide.

Tunander wrote contributions about Northern Europe, Nordic Cooperation,[5] and Scandinavism published by the Norwegian Ministry of Foreign Affairs and the Swedish Olof Palme International Center.

[13] In 2008, Tunander was the subject of some controversy in Norway after publicly questioning the U.S. government inquiry on the 9/11 attacks, suggesting that al-Qaeda may not have been ultimately responsible and citing claims that the World Trade Center had been brought down by explosions.

[15] In the 1980s, a series of suspected foreign incursions in Swedish territorial waters triggered repeated military submarine hunts off Sweden's coast.

Tunander now emerged as a particularly prominent proponent of the idea that many or all of the incursions had in fact been staged by NATO under CIA oversight and with the complicity of Swedish government officials, to be falsely blamed on the Soviet Union.

In contrast with the 1983 investigation that had blamed the Soviet Union, however, he stated that there existed "no solid evidence that allows any conclusions to be made about the nationality of the violating submarines.

In these works, Tunander suggested that Soviet submarines might very well have entered Swedish waters, but the more visible operations were most likely PSYOPs decided by a U.S. "deception operation committee" chaired by CIA Director William Casey, and some of them were run by a CIA-Navy liaison office, National Underwater Reconnaissance Office, headed by Secretary of Navy John Lehman.

Tunander also received support from former Finnish President Mauno Koivisto, who called the operations "provocations" and recalled Soviet leader Yuri Andropov telling him that the Swedes should sink every intruding submarine, so they could see themselves what turned up.