When you argue how NK behaved during “Steipler lifetime”, you need to see – what year was the letter written? Steipler was writing about elections early on – I see one in 1955.
Seemingly Steipler wrote way more about elections than just this one letter. Maybe someone could look up more on his thinking?
here is what I see in secondary sources:
Kreinah D’Igresa letter 739: “I don’t understand the position of the Satmar Rebbe, though I agree with all that was written in his book…nonetheless the people have returned, it is a fact that the people have come back, it is now a reality and therefore whether it was done correctly doesn’t matter, thus now one must vote in order to ensure the safety of Klal Yisrael.
…
all throughout Jewish history Jews were part of the Gentile governments in Europe and of course if one could be in a goyish government he can be in the Jewish government, but nonetheless says the Steipler that one must be very careful that being part of parliament or government is not about getting money, even for the Jews, rather it is about upholding Jewish law.