Three justices on the state's Supreme Judicial Court have announced their impending retirement in the past week. Two more are due to step down at some point next year as they reach the court's mandatory retirement age of 70. As such, Governor Charlie Baker will be able to fill five of seven seats on the state's highest court. Former Supreme Judicial Court chief justice Margaret Marshall spoke with WGBH All Things Considered host Barbara Howard about the changes that the court is soon to undergo.