A book review at FindLaw says that the Leo Strauss decided that the personal is the political, and the political the philosophical because of Heidegger's actions in the 1930's:

Strauss was among the great 'University in Exile' of Jewish academics and intellectuals that formed in the aftermath of the rise of Nazism. Intellectually, he is a direct descendant of the eminent Martin Heidegger; he was, along with Hannah Arendt, chief among Heidegger's acolytes. Betrayed, and also informed, by Heidegger's accommodation with the Nazis, Strauss saw that the political was personal, and that the political and the philosophical could never be separated. And so Strauss emphasized that personal actions were political and that value-laden political philosophy was essential to an understanding of the political.

So then if philosophy is reasonable or logical, so then must be politics and the personal too? I guess it depends on what the meaning of the word 'is' is.  ¶ 3:27 PM