The following letter was published as a photo in an article (See here - the online edition doesn't have the photos of the letters) about R' Chaim Yisroel Eiss Z"L:
To put the letter into context, R' Chaim Yisroel was one of the founding members of the Mizrachi (He apparently had a box full of correspondance with various Mizrachi Gedolim such as R' Reines and R' Mohilever. I do not know where those letters are today (if they still exist.)) He became disillusioned with the Mizrachi when "cultural issues" were raised at one of the Zionist conferences and he went on to become a militant Agudist. You can read about more of his activities in various articles here.
In the original letter (which I have seen), R' Eiss had complained that the Mizrachi leaders such as R' Herzog were being involved with corresponding with him about it first. To which R' Chaim Ozer responded -
."ע"ד מה שכתב הרב ר' מאיר קרליץ שי' בארה"ק ... . מובן כי הישיבות פנו להרב הרצוג אודות סרטיפיקטים ודעתם שיש לו השפעה בענין זה וגם אני כתבתי אליו ולהאגודה כמה פעמים ,באשר במקום של פקו"נ אין מדקדקים על פוליטיקה
Prof. Marc Shapiro explains (I thank him for allowing me to post this) that:
"The letter of R. Chaim Ozer is obviously written with an eye as to who is the recipient, because RCO also engaged in Torah correspondence with R. Herzog (and many other non-Agudists). the letter is probably referring to why he is engaged in political type activities with R. Herzog (which also involved the Mizrachi once removed). "
"I think the main point of the letter is not that RCO is explaining why he did what HE did, he is giving mussar to Eiss, that when it comes to pikuach nefesh, one doesn't concern oneself with politics. The Agudah, especially the German Agudah, we much too separatist for people like R. Chaim Ozer. That is what this letter is about."
(NB: See the letter of R' Chaim Ozer published in Sefer HaZikaron for the Seridei Eish for R' Chaim Ozer's stance on R' Hirsch's Austritt policy.)