&gt; Further, no peace can ever be negotiated because the borders of IS have to keep expanding or the caliphate is no longer valid. That is, Muhammad says all non-believers have to be converted, full stop.<p>I think a lot of liberal media in the West tends to whitewash some of the, shall we say, more unpleasant actions of Islam&#x27;s founder described in the Qu&#x27;ran (violence, child bride, etc).<p>However, the assertion that Muhammad said that all non-believers must be converted is false, full stop.  There is a very famous verse of the Quran addresses this categorically (in the words of Muhammed as supposedly dictated by God):<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Al-Baqara_256" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Al-Baqara_256</a><p>Indeed, the entire tax base of most Muslim empires, most notably the Ottoman, was based on taxing non-Muslims (Muslims were exempt from this tax, but had to serve in the military).  So the rule against forcible conversions was not only stated clearly in the Qu&#x27;ran, but there have been unbroken enforcement of this rule by Muslim empires, kingdoms, and nations from Muhammed&#x27;s time to the modern era, in a large part because of the incentives those entities had in keeping a large number of non-Muslims to tax.  This is not to say that Muslims never forcibly converted people, but it is&#x2F;was widely recognized as being forbidden by the Quran.<p>Now, this is a separate matter from expanding borders.  The Islamic State surely would love nothing more than to establish a caliphate at the farthest historical borders, so N. African up across Spain, Europe across the Balkans up to Vienna, and all of Central Asia.  That said, I can&#x27;t see them ever expanding beyond the Levant, even in the worst case scenario.  Even without a massive Western ground intervention (which would obviously happen if they threatened Spain, if not before), IS would have to conquer Turkey and Iran, and that seems extraordinarily unlikely.