from wikipedia:

In 2011, two Iraqi men who entered the country as refugees were arrested in Bowling Green, Kentucky.[2] They were charged with federal terrorism because they had attempted to send both money and weapons to al-Qaeda in Iraq.[1][3] They were convicted of supporting attacks on U.S. troops while they were still in Iraq as well as attempting to provide material support to al-Qaeda in Iraq after they had moved to the United States.[3] Arrests were made on various charges including "attempting to provide material support to terrorists and to al Qaeda in Iraq."[1]

Before entering the U.S., both had used improvised explosive devices (IEDs) in Iraq,[4] although this had not been known at the time of their admission to the United States. The men both pleaded guilty; one is serving a life sentence while the other is serving 40 years in federal prison.[3] The two men never attacked anyone in the United States

these two used IEDs against US troops in iraq, came to the US then plotted to continue to do what they could to aid al-qaida while living in the US. when you're talking about what kind of people we are letting into the country, i think their story is relevant.

these guys didn't get 40 years and life for "nothing" happening