Still, liberals hoping for a "full-throttled" justice on the left might note that Brennan was actually often least effective when he was most passionate. With Thurgood Marshall, he dissented in hundreds of death penalty cases, a vehemence that mostly irritated his colleagues. His most strident dissents in cases such as National League of Cities v. Usery, in which he accused the majority of exercising "raw judicial power" and "sophistry," wound up alienating them. (Powell in particular came to distrust the way Brennan tried to plant seemingly innocuous language to be harvested later in more expansive opinions, warning his clerks about such Brennan chestnuts in a 1986 affirmative action case.)
So go ahead and daydream about whomever you might consider the most likely successor to Justice Brennan. Just don't expect him or her to be able to change much on the current court. The next justice may wind up frustrated for trying.