Today we know at least 100 Americans have traveled or attempted to travel to Syria for the purpose of joining an Islamist extremist group, either al-Nusra Front, the Islamic State of Iraq and al-Sham (ISIS), or another. We also know that several thousand individuals from European nations have flocked to Syria, and likely now Iraq, for the same purpose. With stunning velocity, the group formerly known as al-Qaeda in Iraq has evolved into the Islamic State of Iraq and al-Sham, and established what it calls a caliphate that spans across portions of Iraq and Syria. While core al-Qaeda leadership may have diminished capacity, it has sought to rebuild as U.S. forces withdraw from Afghanistan, and al-Qaeda affiliates around the world are as strong as ever. ISIS has ruthlessly captured cities, killed indiscriminately, and mobilized thousands of foreign fighters to its cause. It moves its men and arms at will into safe havens on both sides of the Iraqi-Syrian border. As the diaspora of fighters and ideology spreads, there will be long-term consequences and a direct threat to the United States and to the West. It is time for the administration and the Congress to implement a plan to safeguard the homeland before Westerners who have become further radicalized in these conflicts are sent home to carry out attacks.