The killing of Osama Bin Laden and the systematic elimination of numerous senior al-Qaida operatives during the past 12 years have undoubtedly reduced the risk of terrorism. But the bombing at the Boston Marathon in April reminds us that there are so-called “lone wolf” threats out there that are extremely difficult to track, even within U.S. borders.

Daniel Benjamin says combating this strain of violence is particularly challenging because the perpetrators are often radicalized in a vacuum. The former point person on terrorism at the State Department recently talked to Slate’s Jacob Weisberg about the progress that has been made and where the most potent threats remain.

You can also watch the first part of Benjamin’s interview, in which he explains how President Obama has changed up the war on terror from the Bush years. And look out for a third segment where he discusses a highly effective set of tools in the war on terrorism that gets very little attention.