One thing Muslims have been wont to say is that jihad is defensive warfare or, when one differentiates between the greater and lesser jihads (which differentiation is modern and not one made by classical or older sources), the engaging of the lesser jihad when one must act defensively. In contemporary Islam, such a line of reasoning has become common with those who deal with apologetics or who write in English or who deal with non-Muslims: jihad, if using force, is defensive. The problem is that this does not bear out when one looks at history. (This issue is most excellently dealt with by Professor Dr. David B. Cook, of Rice University, in his Understanding Jihad, which We cannot recommend too much.)
One may make the case that Muhammad and his successors desired to dominate/rule the Arabian peninsula to protect Islam from pagans and other non-Muslims who oppose Islam. But the extent of the conquests stretches this excuse very thin. What need had they to conquer all the way to present-day Syria and Iraq?
The Muslims’ further conquests are obviously offensive rather than defensive. Muslim armies spread all the way to present-day Morocco in the west to present-day Pakistan in the east. The conquests went north to Constantinople, the capital of the Byzantine Empire. What justification is there for this spread? If any justification incorporates offensive elements, then the claim that jihad is fought for defensive reasons is false. If it must be defensive, then early Islam’s conquests are illegitimate, which would be a major blow to Muslim pride as this era is seen as one of glory and triumph. The illegitimization of these conquests would also cast significant doubt on the faithfulness of Muhammad and his successors.
The problem does not end with early Islam. Just recently the Ottoman Empire ruled vast non-Muslim areas: Rumania, Serbia, Hungary, and Bulgaria. When these areas wanted to become independent, the Ottoman emperor-caliph declared a jihad to retake the lands. Why would jihad be involved with lands that have nothing to do with Islam? Why did Muslims conquer them in the first place? The same can be asked about Spain.
Dr. Cook states that this argument, that jihad is fundamentally defensive, came about as Muslims began to observe the Europeans, who were disturbingly acting like the early Muslims. Muslims wanted to formulate an argument that would set the early Muslims apart from the Europeans, for Muslims were vociferously attacking imperialism and did not want to admit that Islam itself is imperialistic.
Some Muslims support their claims by saying that Muslims became involved in the Crusades because the Crusaders unprovocatedly attacked the Muslim realms out of religious fanaticism and economic greed. But one ought to ask: how did those lands became Muslim lands? They were Christian for centuries. One also ought to ask: what precipitated the Crusader invasion? Why, it was the personal appeal of the Byzantine emperor to the Pope in Rome for assistance to protect Constantinople from Muslim invasion. As such, the Muslims provoked the Crusades, and the Muslims are the aggressors on two levels: against Constantinople and by having invaded and conquered vast swathes of Christian lands. In this sense, the Crusaders were entirely justified from a moral perspective.
So, one ought not to allow Muslims to get away with skewing facts, history, and ethics.
What the “jihad is defensive” rhetoric attempts to hide is that Islam permits offensive campaigns. Indeed, one may say that Islam commands offensive campaigns: anything and everything until throughout the world the religion is Allah’s and non-Muslims are subdued.