<p>Evidence in the Madrid train bombings points to the participation of a new breed of Islamic holy warrior, unfettered by many of the religious and ideological constraints that defined Islamic terrorism in the past.</p>
<p>These Islamist warriors -- schooled in the North African doctrine known as Takfir wal Hijra and trained by Afghan veterans of al Qaeda -- think, recruit and operate differently from traditional Islamist networks. For Europe, that makes the threat particularly acute. The Takfir movement is strongest in Morocco and Algeria, the primary sources of Muslim immigration to Western Europe. Takfiri theorists openly advocate using immigration as a Trojan horse to expand jihad, or holy war.</p>