YEADON, Pa. — For two Thanksgivings now, Karen Serrano Roberts has been missing from her family’s dinner table in Yeadon. It’s beginning to look like this will be a second Christmas away from home, too. Karen Roberts, a Mexican national who has lived in the United States for most of her life, has been stranded in Mexico for the last 18 months, separated from her U.S. born husband and five children due to her immigration status. Born in Puebla, Mexico, in 1991, Roberts, 31, was brought to the States when she was 4 without legal documents, she said. For part of that trip, she said, “I was in the...