BostonGlobe.com Political Headlines - August 20, 2014 August 20, 2014 Here are the top political headlines from BostonGlobe.com today: Democratic candidates for governor spar in debate: Martha Coakley, Steve Grossman and Donald Berwick talked about a range of topics ahead of the Sept. 9 primary. David Scharfenberg reports. Islamist militants execute N.H. reporter James Foley: The Islamic State distributed a video that said Foley’s apparent beheading was retaliation for recent US airstrikes in Iraq. Travis Andersen and Bryan Bender detail the latest. N.H.-bound Rick Perry set to capitalize on indictment: In an odd political twist, Perry’s clash with the law may be his best selling point in New Hampshire. Noah Bierman reports.