Peter L. Bergen

The centerpiece of the Bush administration's case for going to war in Iraq was Secretary of State Colin Powell's presentation to the U.N. Security Council on February 5, 2003, six weeks before the invasion.

The rise of ISIS starts with a Jordanian thug named Abu Musab al-Zarqawi who founded ISIS' parent organization, al Qaeda, in Iraq. What gave Zarqawi the opportunity to create al Qaeda in Iraq? It was, of course, George W. Bush's decision to invade Iraq in 2003.

Every lethal terrorist attack in the United States since 9/11 has been carried out by an American citizen or a legal permanent resident, not by recent immigrants or by refugees. So tamping down immigration won't fix the real issue, which is 'homegrown' terrorism.