Story at the Weekly Standard. The memo, written by David Brock, which was sent by someone to Hillary Clinton's email account, is here. (I haven't seen any claims that Clinton herself participated in the efforts outlined in the memo.)
In several contexts, I have opposed movements to reform or regulate the SCOTUS or recuse particular SCOTUS justices because I have doubted the integrity of the movements -- that is, because I've concluded that the court and its justice needed to be protected from what are really partisan attacks. This "hard ball" memo makes my concerns seem plausible.