A divided state appellate panel has dismissed a lawsuit accusing Goldman Sachs & Co. of tricking insurer ACA Financial Guarantee Corp. into insuring a complex mortgage-backed security that the bank had designed to fail, ruling that ACA should have done more to protect itself.

The 3-2 Appellate Division, First Department, panel yesterday reversed Manhattan Supreme Court Justice Barbara Kapnick’s (See Profile) April 2012 decision in ACA Financial Guaranty v. Goldman Sachs, 650027/11, allowing the case to go forward.