This article at Grist examines the reasons that environmental groups have been slow to criticize the proposed border wall between the U.S. and Mexico, which will likely have extremely destructive consequences for the wildlife in the area. The reason, writes Glenn Hurowitz, is that they don’t want to invite the kind of bitter controversy over immigration that embroiled the Sierra Club a few years back. The piece also points out, however, that many immigration restrictionists are skeptical that a wall will actually make a significant difference compared to other measures like sanctioning employers who hire illegal immigrants.