Freedom of speech and freedom of religion are key rights guaranteed by the U.S. Constitution. Unfortunately, there are some in our country who have used the Constitution as an enabling device to further their advocacy of violent ideologies and actions.

Anwar al-Awlaki was born in New Mexico, attended Colorado State University, and worked at mosques in San Diego and Virginia. He was also a jihadist propagandist and, according to the United States government, a “key leader” of al-Qaeda in the Arabian Peninsula.

Al-Awlaki died in a 2011 U.S. drone strike in Yemen. But before he moved to Yemen in 2004, al-Awlaki preached at U.S. mosques, where he also reportedly met with future 9/11 hijackers. He also directly influenced many other extremists. Umar Farouk Abdulmutallab, who attempted but failed to blow up an airplane with explosives hidden in his underwear, allegedly received direct instructions from al-Awlaki. Nidal Hasan, who shot and killed 13 people in his 2009 attack at Fort Hood, called al-Awlaki a teacher and a friend. Faisal Shahzad, the failed Times Square bomber, also claimed to be under al-Awlaki’s influence.

Al-Awlaki may be gone, but other Islamist propagandists are following in his footsteps. Ahmad Musa Jibril is an American Islamist preacher who may well become the inheritor of al-Awlaki’s mantle. From his home in Dearborn, Michigan, Jibril has produced Internet lectures advocating an extremist Salafist version of Islam. His YouTube sermons have praised Syrian fighters as “real men,” while his tweets are filled with anti-West invective, such as this January 2014 post.

Jibril differs slightly from al-Awlaki in style. He does not specifically advocate violence, but he praises Islamist ideals and thereby inspires his followers to violent jihad. The International Centre for the Study of Radicalisation (ICSR) dubbed Jibril part of “a new set of spiritual authorities” influencing Westerners to become foreign fighters in the Syrian conflict. Sixty percent of foreign fighters in Syria follow Jibril on Twitter, according to an April 2014 ICSR report. Jibril “bridges the gap” for Westerners who may not understand Arabic, said the ICSR's Shiraz Maher. Jibril “provides the political and theological justification” and “comfort” to jihadists, said ICSR director Peter Neumann.

While al-Awlaki eventually moved to Yemen, Jibril appears content to continue living in Michigan. Jibril’s Facebook and Twitter accounts have not been updated in more than a year, attributable to June 2014 court-ordered restrictions following violations of his probation from a  2005 fraud conviction for which he spent seven years in prison. Federal Judge Gerald Rosen reportedly restricted Jibril’s social-media access to ensure he does not influence others.

The accounts may be inactive, but they continue to influence foreign fighters. In June, for example, three British women—Sugra Dawood, Zohra Dawood, and Khadija Dawood—flew to Turkey with their combined nine children in order to cross into Syria. One of Sugra Dawood’s children, 14-year-old Ibrahim Iqbal, reportedly “liked” Jibril’s Facebook page.

Jibril has yet to return to his digital pulpit since the court-ordered restrictions expired in March, but his audience continues to grow. His Facebook page has more than 240,000 likes, up from about 217,000 in July 2014. His YouTube page has more than 9,500 subscribers, and his Twitter account has more than 28,000 followers.

Al-Awlaki made the leap from rhetorical to physical support for AQAP, while Jibril remains an ideological supporter of general jihadism rather than a specific group. Still, the similarities between them are clear, as illustrated below.

Al-Awlaki eventually wore his militancy on his sleeve, making it easier for U.S. authorities to label, track, and eventually kill him. Islamists like Jibril—who just avoid crossing the line from repugnant-yet-protected speech into explicitly violent rhetoric—are harder to stop.