Do Liberals Depart from the Party Line?

Glenn Reynolds links to Marc Thiessen’s Op Ed that points out the consistency of liberal justices as compared to the inconsistency of conservative ones:

Just compare the records over the last three decades. Democrats have appointed four justices — Ruth Bader Ginsberg, Stephen G. Breyer, Elena Kagan and Sonia Sotomayor. All have been consistent liberals on the bench. Republicans, by contrast, have picked seven justices. Of Ronald Reagan’s three appointees (Sandra Day O’Connor, Antonin Scalia and Anthony M. Kennedy) only Scalia has been a consistent conservative. George H.W. Bush appointed one solid conservative (Clarence Thomas) and one disastrous liberal (David Souter). With George W. Bush’s appointments of Samuel A. Alito Jr. and Roberts, conservatives thought finally they had broken the mold and put two rock-ribbed conservatives on the bench — until last week, that is, when Roberts broke with the conservatives and cast the deciding vote to uphold the largest expansion of federal power in decades.

When the conservatives got their opportunity to overturn Roe v. Wade, three Republican appointees wrote a joint opinion that upheld the essential holding of Roe.  The Republicans just had an opportunity to get their biggest victory in at least a half century and John Roberts had a failure of nerve.

While Thiessen ably explores the reasons for this disparity, I am here interested in a different question.  Are there any important cases where a liberal justice has departed from the liberal party line?  

Let me start out by putting to the side the decisions of Justice White, who was appointed by John Kennedy and opposed Roe.  White was appointed in a different era, by a more moderate President, and his decision was not that of a liberal who departed from the party line.  (For what it is worth, White was the Chairman of the Conservative Party of the Yale Political Union in Law School.)   On the other hand, perhaps some of Justice Ginsburg’s decisions on criminal law would count.  But are any of these very important?