SAN FRANCISCO — Lawyers for McDermott Will & Emery have the right to contest the 2012 disqualification order that led to the firm getting sued by its former client, a state court judge ruled this week.

McDermott, which is fighting malpractice and breach-of-duty claims, wants to challenge a federal judge’s conclusion that it improperly represented clients with adverse interests. But MotionPoint Corp., the former client, was hoping for a court order barring McDermott from relitigating old issues.