There are more reasons to reject Michael Mukasey's nomination than his evasive answers on waterboarding and unconstitutional expansive views of federal power. Years ago, Michael Mukasey defended the indefensible when his friend, Rudolph Giuliani, then a prosecutor, began subpoenaing defense lawyers before grand juries.

It was one of the more substantial overreaches of the Giuliani years. And it is of particular relevance in today's criminal cases that bear the terrorism...