For library-opera house on U.S.-Canadian border, a new chapter

The skinny black line that runs along a hardwood floor in the Kenneth Baldwin International Reading room has taken on added significance this year as border officials contemplate a crackdown on three unguarded streets linking Derby Line and Stanstead, Quebec. What many here fear is that border authorities will close the book on an unspoken agreement under which locals can come and go from the library without reporting to customs, even if they cross the border en route.