[AnetTeilor]

Sweden was extremely scared of Russia throughout the 19th century. This was reflected in basicly anything they did. T'was just a few years earlier that the Russians recieved all of Finland as well as what was then a suburb of Stockholm (Åland, the island between Finland and Sweden).
They also landed near stockholm in that war.

Was a while since I read about this but:

There was a somewhat strong movement to join the central powers during ww1 in Sweden, those advocating it where refered to as "Activists".
These had the support of the king (and more importantly the Queen who was German herself).
The war years saw a rather unstable political structure and as I recall Sweden changed governments 3 times between Reactionary/conservatives (these where hand picked by the king), liberals and Socialists (the socialist party was also split in 1917 in an incident which according to some had Sweden at the brink of a revolution).