[Excerpt:  "All this is just further proof that Al-Awalki has now surpassed Osama bin Laden as the world's most influential Islamic jihadist. He's American born, fluent in English and media savvy: a perfect storm that has enabled him to act as a pied piper in recruiting young Western Muslims." ]

Federal prosecutors this week announced two different terrorism cases involving American citizens who converted to Islam and were allegedly plotting acts of violent jihad.

In one case, a Virginia man was charged with trying to travel to Somalia to join forces with Al Shabab, an Al Qaeda-linked Islamist militant group that the US has designated a terrorist organization.

In the second, Alaska resident Paul Rockwood pleaded guilty to assembling a hit list of 15 targets for assassination or bomb attacks of those within the US who had desecrated Islam. He has agreed to serve an eight-year prison sentence.

In Virginia, Zachary Chesser, a former George Mason University student, has been charged with providing material support to the Somali-based terror group he reportedly sought to join.

The cases share a common denominator: Both men appear to have had contact with US-born militant cleric Anwar al-Awlaki, who is believed to be in a remote part of Yemen and head of Al Qaeda in the Arabian Peninsula. His speeches and sermons circulate internationally via a network of militant Islamic websites and blogs.

Officials suspect Mr. Awlaki was a motivating force behind the shooting rampage in November by Maj. Nidal Hasan at Fort Hood, Texas. The attack left 13 US service members dead.

Awlaki is also believed to have played a role in preparing Nigerian Umar Abdulmutallab for his attempt to blow up a jetliner near Detroit on Christmas Day. Last week, Awlaki was named by the US Treasury Department as a “specially designed global terrorist.”

While these actions and investigations suggest US officials remain vigilant against home-grown threats from militant Islam, they do not address a more fundamental question: What would cause a life-long American to apparently choose the radical Islamic side in the US battle against Al Qaeda?

Mr. Rockwell’s plea agreement says that while residing in Virginia he converted to Islam and became a “strict adherent to the violent Jihad-promoting ideology of cleric [Awlaki].”

The document adds: “This included a personal conviction that it was [Rockwood’s] religious responsibility to exact revenge by death on anyone who desecrated Islam.”

Even after he moved to King Salmon, Alaska, Rockwell still followed Awlaki’s ideology, “including devotion to [Awlaki’s] violence-promoting works, 'Constants on the Path to Jihad' and '44 Ways to Jihad.' "

All this is just further proof that Al-Awalki has now surpassed Osama bin Laden as the world's most influential Islamic jihadist. He's American born, fluent in English and media savvy: a perfect storm that has enabled him to act as a pied piper in recruiting young Western Muslims.