DES MOINES — The Iowa Senate passed legislation Monday intended to strengthen “qualified immunity” for law enforcement officers who take forceful action in situations where state law is “not sufficiently clear” to understand their conduct might violate someone’s constitutional protections.Majority Republicans said the statutory language is needed to clarify court rulings and provide “balance” in cases where the law was not “clearly established” at the time of an incident giving rise to a claim against an officer.