Quoting an aperçu by Marc Shapiro:
According to the Steipler, R. Isaac Zev Soloveitchik (the Brisker Rav) also wanted to leave Israel during the 1948 war, and even traveled to Haifa to receive his exit permit. In the end, he was prevented from leaving for reasons beyond his control, and didn’t continue his efforts in this regard. The Steipler explained that his desire to leave Israel was not because he was afraid but because he thought that the halakhah requires one to leave a place of danger to life.
[A. Horowitz, Orhot Rabbenu, vol. 5, p. 74.]
Marc Shapiro adds:
I have difficulty understanding this view, as it would mean that all the Jews in Israel would have been required to leave. Presumably, R. Velvel’s point was that one who has no civilian or military role has to leave, since there is no justification for such a person to put his life in danger as he is not in any way contributing to the military cause.
Myself, I doubt Rabbi Soloveitchik would allow even soldiers to do soldiering. But a myopic perspective ignoring the importance of the home front (unless they were saying Tehillim) sounds exactly like the unearthly, reality-denying nonsense one would expect out of him!
Following this logic, why didn’t the Brisker defeatists run away during the Gulf War (as rumor has it of S. Helbrantz, cult leader of “Lev Tahor”), eh?! Or similar “sakanah” situations?
Indeed, we once quoted the Brisker Rav as saying: “… every Jew dwelling in the land of Israel is guilty of Zionism“.
Shedding new light, perhaps Rabbi Soloveitchik meant that even his own students didn’t inherit his deficit of true (!) Bitachon in Hashem and in the special Divine providence over the Jews in Eretz Yisrael promised in the Torah.
(See a similar cause for hope here.)