Watch Video | Listen to the AudioHARI SREENIVASAN: One of the most contentious issues during the current presidential election is how to confront ISIS and who was responsible for the rise of the extremist group.
Margaret Warner reports.
MARGARET WARNER: This was the scene recently in a village not far from Mosul in Northern Iraq. Newly uploaded video purports to show Islamic State fighters doing battle with Iraqi Kurdish forces. Despite battlefield setbacks in Iraq and Syria, the militant group remains lethal.
How to fight ISIS has become a central theme in the 2016 U.S. presidential race.
DONALD TRUMP (R), Presidential Nominee: ISIS is honoring President Obama. He is the founder of ISIS. I would say the co-founder would be crooked Hillary Clinton.
(CHEERING AND APPLAUSE)
MARGARET WARNER: That was last week. Yesterday, Republican nominee Donald Trump delivered a fuller anti-ISIS message in Youngstown, Ohio.
DONALD TRUMP: My administration will aggressively pursue joint and coalition mi