Armed with a new 10-page report he commissioned, Maricopa County Sheriff Joe Arpaio said Thursday he suspects the birth certificate President Obama released last year is a “computer-generated forgery” — and also raised questions about the authenticity of the president’s selective service registration card. In an extensive — and at times combative — press conference in Phoenix, Sheriff Arpaio repeatedly said he is not questioning the president’s legal status under the Constitution nor alleging fraud...