Swedish trade with Germany, particularly in iron ore, eventually led to exports of food to Sweden being greatly reduced, especially after America's entry into the war in 1917.
[8] Significant numbers of Swedes also took part as volunteers in the Finnish Civil War, with the 350-strong Swedish brigade playing a role in the decisive Battle of Tampere.
[12] Oscar's successor, King Gustaf V was married to a German, Victoria of Baden, a first cousin of Kaiser Wilhelm II, and the Swedish Marshal of the Realm, Ludvig Douglas, was also known to be a strong proponent of an alliance with Germany.
In November 1910, the general staffs of Germany and Sweden had even met in secret to discuss a joint offensive against Saint Petersburg, but the meeting ended without a binding agreement being reached.
In response, King Gustaf gave a speech written by the ardently pro-German explorer Sven Hedin in the courtyard of the Royal Palace in Stockholm that argued for higher military spending.
[14] During the July Crisis, both King Gustaf and Knut Wallenberg, the Swedish foreign minister, gave assurances to the Central Powers that in a war between Germany and Russia, Sweden would never stand on Russia's side, and that although Sweden would issue a declaration of neutrality at the start of the conflict she would retain the freedom to take other action later.
[15] The assurances given by King Gustaf and Knut Wallenberg led the German secretary of the foreign ministry, Gottlieb von Jagow, to believe that Germany would be supported by Sweden in the upcoming conflict.
On 2 August, however, Wallenberg, speaking to the British minister in Stockholm, had repeated his assertion that if Sweden were driven into the war, she would never fight on the side of Russia.
A further joint declaration was made by the three kings of Denmark, Norway, and Sweden in 18 December 1914,[17] and the Swedish army units that had been sent to the Finnish border were stood down.
[18] In early 1915, Arthur Zimmermann, the Under-Secretary of State at the German foreign ministry, approached Hammarskjöld, who was on a visit to Berlin, with an offer of potentially forming a "Nordic Block" under Swedish leadership in return for an alliance between Sweden and Germany.
Prince Max had been instructed by Kaiser Wilhelm II and Erich von Falkenhayn, who wished to integrate Sweden into the German Mitteleuropa, to obtain an alliance with a view to a joint attack on St. Petersburg, in return Germany was willing to offer material and military support as well as the promise of Åland (which contained a Swedish-speaking population, and the fortification of which by the Russians during 1915 caused concern in Sweden[20]), an adjustment of the frontier, and an independent or autonomous Finland.
[19] On 1 December 1915 two leading pro-German Swedish political figures, the Social Democrat Otto Järte, and the conservative editor Adrian Molin, had an audience with King Gustaf in which they urged him to join the war on Germany's side.
Despite claiming that they would end the practice in late 1915, a scandal erupted in 1917 when it became known that a telegram from the German chargé d'affaires in Argentina, Count Luxburg, to Berlin proposing that certain Argentine ships be "sunk without trace" had been transmitted via the facilities of the Swedish foreign ministry.
In 1913 a special naval aviation corps, the "Marinens Flygväsende" (MFV) was founded in Stockholm,[26] and by 1914 this had expanded to include, in addition to the Blériot, two Henri Farmans and a Donnet-Leveque flying boat, all of which were based at Oscar Frederiksborg.
[16] Eventually Germany relented in return for a promise that Sweden's lighthouses in the Øresund would be switched off and markers showing the way through the channel would be removed if the Royal Navy was sighted in the sound.
[27] In October 1915 British submarines operating in the Baltic successfully sank several German cargo ships as well as the armoured cruiser SMS Prinz Adalbert.
[29] Another concern was that British and French merchant ships, which had been stranded in the Baltic when war began, were being brought back to the UK and France via the Kogrund Channel (Kogundsrännan) running through the Øresund straits, which the Swedes believed might invite a German response.
[30] Sweden eventually mined the Kogrund Channel in a move announced on 28 July 1916, closing it to all but Swedish ships which would be led through the minefields by pilots.
The most well known among these casualties was the German writer Gorch Fock (real name Johann Kinau), who was among the crew of the sunk light cruiser SMS Wiesbaden and whose body was found on the Swedish shore near Fjällbacka.
[5] Despite the food shortage, Hjalmar Hammarskjöld had continued to resist an agreement that might loosen the blockade in return for reducing exports to Germany due to fear of angering the Germans and being seen as favouring the Allies.
[11] Hammarskjöld's government also became weakened around this time when the "Luxburg Affair",[36] involving Swedish facilities being used to transmit secret messages targeting allied shipping for the Germans, became known.
In early 1917, a combination of protests over food shortages[37] and the failure of the Riksdag to approve increased defence spending, forced Hammarskjöld to resign.
[38] King Gustaf called on the conservative Ernst Trygger to form a government, however he lacked the necessary support in the Riksdag to do so, so he was instead replaced by Carl Swartz in March 1917.
In May 1917 disturbances hit the island of Seskarö in northern Sweden, where fighting broke out between the local population and the military in which the police had to intervene.
[23] The largest disturbance occurred on 5 June 1917, when 20,000 people assembled near the Riksdag in Stockholm to hear the response of Carl Swartz to a request from Hjalmar Branting to introduce universal suffrage and constitutional reform, and were dispersed by mounted police.
[7][39] Following Edén's election disturbances subsided as the social-democrats stopped supporting them, though demands for reforms, including an 8-hour day and improved living conditions, continued.
Swedish poets, including Karl Gustav Ossiannilsson, Bertil Malmberg, and Ture Nerman used the medium of war-poetry to explore various themes.
The large conservative outlets, including Svenska Dagbladet, Aftonbladet (which was majority-owned by German interests), and Nya Dagligt Allehanda had been broadly pro-German.
[23] The rise to power of social-democratic politicians also permanently altered the Swedish political landscape, as many aspects of Liberal policy were implemented, and universal suffrage was accepted.