Effective for your own people, but not your neighbors. For example. Let's take WWII for example. If your neighbors house is on fire would you not try to assist them, or would you shut your blinds because that fire is too bright in the middle of the night. That was the official attitude of Switzerland while Europe burned under Nazi occupation.
Isolationism alone is not an end all be all answer, we must use our best judgement to assess if assistance is necessary in international relations. It is true, that it is sometimes best to do nothing, (suppose your neighbor is an arsonist) but time and again people seem to forget that leaving nations to their cruelty because of sovereign rule has lead to catastrophe. For all of Europe (Nazi Germany) for all of Eurasia (Soviet Russia/Stalin), Manchuria (Japan), Rwanda, Mao's Cultural Revolution, North Korea, Burma... the list goes on, and by sheer numbers the consequence of inaction cost more than action.
And your evidence that Switzerland would have helped prevent any of that?
While we're throwing unbacked statements around, had the US tried some "isolationism" in WW1, WW2 never would have happened! The Germans wouldn't have been forced to sign the Treaty of Versailles and the conditions that led to the rise of the Nazis wouldn't have existed.
Isolationism alone is not an end all be all answer, we must use our best judgement to assess if assistance is necessary in international relations. It is true, that it is sometimes best to do nothing, (suppose your neighbor is an arsonist) but time and again people seem to forget that leaving nations to their cruelty because of sovereign rule has lead to catastrophe. For all of Europe (Nazi Germany) for all of Eurasia (Soviet Russia/Stalin), Manchuria (Japan), Rwanda, Mao's Cultural Revolution, North Korea, Burma... the list goes on, and by sheer numbers the consequence of inaction cost more than action.