Here are some book and dissertation sources to get you started. This is not an exhaustive list!
Ethnic leadership and Midwestern politics: Scandinavian Americans and the Progressive Movement in Wisconsin, 1890-1914
Brøndal, Jørn, 2004.
Diplomatic relations of the United States with Sweden and Norway, 1814-1905
Hovde, Brynjolf J, 1921.
Scandinavians in the state house: how Nordic immigrants shaped Minnesota politics
Bergman, Klas, 2017.
Cross-border commemorations: celebrating Swedish settlement in America
Hjorthen, Adam, 2018.
Swedish politics during the 20th century
Hadenius, Stig, 1988.
Modern welfare states: politics and policies in Social Democratic Scandinavia
Einhorn, Eric S.; Logue, John, 1989.
The Swedes in Illinois politics, an immigrant group in an American political setting.
Hendahl, Reuel Gustav, 1932.
The religious origins of democratic pluralism: Paul Peter Waldenström and the politics of the Swedish Awakening 1868-1917
Säfström, Mark Daniel, 2010.
Partners in progress: a chapter in the American-Swedish exchange of knowledge
Olsson, Nils William, ed; Kastrup, Allan, ed.; 1977.
Swedish patriots and founders of the United States
Lesley, Allen, 1976.
Sweden and the American Revolution
Benson, Adolph, 1992.
The development of the Swedish welfare state in a comparative perspective
Korpi, Walter, 1990.