Why is the Islamic State so difficult to destroy?

Despite the expected loss of its two largest urban strongholds, the Iraqi city of Mosul and the Syrian city of Raqqa, the extremist organization Islamic State has demonstrated a high level of flexibility and survivability that will not be easily overcome. The group's staying power comes from a combination of insurgents and digitally connected jihadists around the world, small cells of extremists fleeing Iraq and Syria and those who have never been there, according to the Associated Press. Since its territory in Iraq and Syria began to shrink in the last year, the goal of the Islamic State is to maintain its local and global base. About 100 Islamic State fighters from Syria and Iraq arrived in Afghanistan in February, and another 20 arrived at the end of March, according to a UN report published last Sunday. Although the group is not popular with average Afghans, it appeals to young people and receives significant funding from Islamic State headquarters. New fighters are offered between $500 and $600 a month, three times the amount offered by the Taliban.

The UN report states that the Islamic State has warned its contingent in Afghanistan that it will soon have to finance itself, which is a bad sign for an organization that once received millions of dollars from oil, ransom and extortion, according to the AP. Al-Qaeda, today known as Hayat Tahrir al-Sham, is gaining strength in some parts of Syria and in recent days has been targeting "organizational cells" of the Islamic State in that country, in order to attract its fighters. Al Qaeda and the Islamic State split in 2014, less over differences in ideology and more over disagreements over timing and tactics. Bruce Hoffman, head of the security studies department at Georgetown University, said "the differences between the two groups are more a matter of style and tone than substance," according to the AP. Many foreign fighters of the Islamic State, especially those from Europe, came to Syria at one time to join Al Qaeda, but joined the Islamic State, which they believed to be the winning side. Hoffman believes that their return to the ranks of Al Qaeda will not be particularly difficult. While Islamic State's propaganda materials used to show bountiful harvests, children playing and free health care in order to win over supporters, lately airstrikes on its positions have been shown to send a message about the need for revenge. The London Bridge attack in June was described by Islamic State as revenge against the US-led international coalition and promised more violence in the future.