In the years since the Holocaust, fears have increased that the window of opportunity to bring Nazi war criminals to justice is closing — perpetrators and witnesses are dying, and many countries’ political will to bring charges against old men and women is diminishing. Last week, the window opened a little. Germany, following the conviction in May of accused death camp guard John Demjanjuk, announced that it would reopen dormant investigations of hundreds of other guards at death camps during World War II. “It certainly has symbolic significance,” said Menachem Rosensaft, who teaches law at Cornell University and Columbia University, and is a leader in “Second Generation” activities of children of Holocaust survivors. He called the expansive German verdict “a very positive development, many decades too late …[it] should have been made many years ago. Other countries may follow suit — I don’t think they’re likely to.”