When the United States withdrew its last convoy of troops from Iraq in December 2011, Iraq was left in a tenuous state. The presence of a large foreign occupying army had calmed tensions between Sunni extremists and Iraq's Shi'ite-led government, but today, the civil war in Syria attracts radical Sunni foreign fighters to Iraq (and elsewhere in the region). (In 2012, the government of Iraq took action, ordering border guards to prevent adult men crossing from Syria into Iraq, but it doesn't look like it was all that effective.) Iraq's internal political balance, very carefully negotiated between Sunnis, Shi'ites, and Kurds, could easily be upset, and there are groups actively trying to do just that. Al Qaeda in Iraq, thought to be decimated during the American occupation, has been resurgent since the withdrawal, and is active in both Iraq and Syria. A series of terror attacks this July killed 1,000 Iraqis, an amount of terrorist-related violence not seen since 2008.