SPRINGFIELD — Senate lawmakers this week are schedule to debate and potentially approve House amendments to a bill meant to serve as a “statutory backstop” to prevent future litigants from seeking reimbursement for now-unconstitutional compulsory union dues.The bill amends the state law governing public employee unions. It is in response to the U.S. Supreme Court’s decision in June 2018 that struck down its 40-year precedent in Abood v. Detroit Board of Education.The high court’s decision in …