Starting Monday, February 16, americancity.org will feature the first of a series of new columns, where our writers offer opinion, commentary and plenty of opportunity for debate. These topically organized columns range from immigration to politics, urban economics to poverty, the environment to culture, all, of course, with the expertise and urban focus you’ve come to expect from Next American City. Maggie Tishman’s “Borderline,” a column focused on immigration in urban areas will kick things off.