The meaning of the term continues to be debated, and some view it as problematic. Several scholars consider Islamophobia to be a form of xenophobia or racism, although the legitimacy of this definition is disputed. Some scholars view Islamophobia and racism as partially overlapping phenomena, while others dispute the relationship, primarily on the grounds that religion is not a race. The causes and characteristics of Islamophobia are also subjects of debate. Some commentators have posited an increase in Islamophobia resulting from the September 11 attacks, the rise of the Islamic State of Iraq and the Levant, and other terror attacks in Europe and the United States by Islamic extremists. Some have associated it with the increased presence of Muslims in the United States and in the European Union, while others view it as a response to the emergence of a global Muslim identity.