This dilemma, some social theorists would conclude, may very well play into the initial plans of the acting terrorist(s); namely, to delegitimize the state and cause a systematic shift towards anarchy via the accumulation of negative sentiments towards the state system. Religious terrorism
According to the Global Terrorism Index by the University of Maryland, College Park, religious extremism has overtaken national separatism and become the main driver of terrorist attacks around the world. Since 9/11 there has been a five-fold increase in deaths from terrorist attacks. The majority of incidents over the past several years can be tied to groups with a religious agenda. Before 2000, it was nationalist separatist terrorist organizations such as the IRA and Chechen rebels who were behind the most attacks. The number of incidents from nationalist separatist groups has remained relatively stable in the years since while religious extremism has grown. The prevalence of Islamist groups in Iraq, Afghanistan, Pakistan, Nigeria and Syria is the main driver behind these trends.Five of the terrorist groups that have been most active since 2001 are Hamas, Boko Haram, al-Qaeda, the Taliban and ISIL. These groups have been most active in Iraq, Afghanistan, Pakistan, Nigeria and Syria. Eighty percent of all deaths from terrorism occurred in one of these five countries. In 2015 four Islamic extremist groups were responsible for 74% of all deaths from Islamic terrorism: ISIS, Boko Haram, the Taliban, and al-Qaeda, according to the Global Terrorism Index 2016.
A. J. Coady has written that the question of how to define terrorism is "irresolvable" because "its natural home is in polemical, ideological and propagandist contexts".Experts disagree about "whether terrorism is wrong by definition or just wrong as a matter of fact; they disagree about whether terrorism should be defined in terms of its aims, or its methods, or both, or neither; they disagree about whether states can perpetrate terrorism; they even disagree about the importance or otherwise of terror for a definition of terrorism." State terrorism
State terrorism refers to acts of terrorism conducted by a state against its own citizens or against another state. United Nations
In November 2004, a Secretary-General of the United Nations report described terrorism as any act "intended to cause death or serious bodily harm to civilians or non-combatants with the purpose of intimidating a population or compelling a government or an international organization to do or abstain from doing any act". The international community has been slow to formulate a universally agreed, legally binding definition of this crime. These difficulties arise from the fact that the term "terrorism" is politically and emotionally charged. In this regard, Angus Martyn, briefing the Australian parliament, stated,

The international community has never succeeded in developing an accepted comprehensive definition of terrorism. During the 1970s and 1980s, the United Nations attempts to define the term floundered mainly due to differences of opinion between various members about the use of violence in the context of conflicts over national liberation and self-determination.