NILES — Author Paul Rohrbaugh of New Middletown first became aware of the McKinley National Birthplace Memorial when he needed to draft a fourth-grade report about a United States president. “I was awestruck by the white marble building in the middle of Niles and that motivated me to learn more about President McKinley over the years,” he said. After 21 years working at Youngstown State University, including as a librarian in the Beeghly College…