Following up on the previous post, let me elaborate as to why I believe that Gen. Amnon Lipkin Shachak was not descended from Rav Yisrael Salanter, aka Rabbi Israel Lipkin Salanter.
1) There is no good proof for it. One site making the claim gives the source as 'personal knowledge', while others, such as Hebrew Wikipedia pages here, and here, give no source at all.
2) The Wikipedia pages already, in the past, had stated that he was of Chassidic descent (and still incorporates that in them even after recently tacking on a new claim that he was descended from Rav Yisroel Salanter).
They can't both be right. You can't have it both ways.
The Chassidic descent info was there first and I assume therefore that it is correct, while the Rav Salanter claim came later. I suspect what happened is that someone thought, well his name is Lipkin and Rav Yisroel's name was Lipkin, so therefore they must be connected. And then wrote or reported it. And then others just repeated it without subjecting it to scrutiny.
3) While the general came from a seventh generation Israeli family, Rav Yisroel Salanter's family was not in Eretz Yisroel until later on in the modern era.
4) The general's forebears came from the Pinsk area, while Rav Yisroel came from other Lithuanian areas. Keep in mind that in those days people didn't get around as easily as they do today.
5) See the comments of יעקב135 in a discussion of the matter at an Israeli website.
Update: A fine Israeli website focusing on Rabbinic genealogy, by בנימין מפתח תקוה, concurs.