It's exactly the current crisis that led me to recall this almost-forgotten song that seems so appropriate now. When I first heard it as a fifteen-year-old, it sparked a lifelong interest in the German language. I've never become fluent. but I'm fascinated by German's grammar and can appreciate (with translation help) some beautiful German poetry in a way that I never could have without my eventual four semesters of college German.
When I first saw the movie "Cabaret", it occurred to me to compare this song to "Tomorrow Belongs to Me", sung by a band of Hitler Youth, but I finally dismissed it. There wasn't a whole lot of Nazi sympathy in post-war West Germany at the time this song was written there and became popular there [athough the singer was Croatian]; I prefer to think the nostalgia was for pre-Nazi [relative] peace and prosperity. Fortunately the Nazi horror and the post-war division are "alles vergehen": past, but still haunting our dreams.
Speaking of that, the penultimate line is my favorite. I find it impossible to translate readily because I can't get out of my mind that "wird", besides being the future-tense auxiliary, also means "become"; I keep thinking "wird das alles vergangen". The best I can do to comprehend "wird das alles vergeh'n" is "this will all become a bad dream of the past". Maybe the English aphorism "this, too, shall pass" will serve.