If Sweden had joined Norway's 1940 campaign

How would World War II's Norway campaign change if Sweden helped Norway?

Swedish participation could make German success far costlier by opening Allied logistics, threatening sea supply, and tying down forces needed elsewhere.

Swedish territory and railways could connect northern and southern Norway, allowing troops and equipment to move between fronts. Swedish naval forces operating from the Baltic, alongside the Royal Navy on the other side, would threaten Germany's seaborne supply to southern Norway and remove a secure flank. Swedish airfields would create additional Allied operating bases, while Swedish iron ore would become another German concern. A longer campaign could force Germany to choose between committing more resources to Norway and preserving its plans in France. Even a German victory in France could then leave an Allied Scandinavia available for operations against German industry. British and French withdrawal would also become politically harder if it meant abandoning Sweden and potentially Finland as well as Norway. German defeat in Norway is presented as a real possibility, with the explicit warning that Swedish intervention would still carry risks.