SPRINGFIELD — A court’s instructional error, combined with closely balanced evidence, merits a new trial under the plain-error doctrine.This was the decision of a divided Illinois Supreme Court in a case involving a man who was convicted of resisting arrest.In a 43-page opinion issued today, the state’s top court voted 4 to 3 on the question of whether the court’s failure to properly advise jurors of the Zehr principles during voir dire could alter the outcome of a trial.The Zehr principles are …