I see people still aren't interested in discussing the topic at hand, and even armageddonman hasn't yet engaged with me on the topic. So, I'm going to give it another try.
In most commentaries, the authority for jihad is mainly described as coming from Qur'an 2:190-194. In Yusuf Ali's translation,
Now, to be fair to armageddonman, Salafist interpretation of the above verses is along the lines he describes. In the Saudi-sponsored and Wahhabi-approved Hilali-Khan translation of the Qur'an, for instance, the above verses are annotated as follows:
Similarly, Abul Ala Maududi, the founder of Pakistan's Islamist Jamaat-e-Islami party, wrote in his 1930 pamphlet
Jihad in Islam:
(Incidentally, the whole thing is pretty tedious that way, and the "revolutionary" terminology is intentional. I swear you could do a cut and replace the Islamic terms with Communist terms, and you'd have something straight out of old Soviet propaganda)
Sayyid Qutb, the main Islamist thinker of the Muslim Brotherhood, built on the above concept of jihad, saying things like "A Muslim goes to war in order to fight in the way of Allah, to exalt Allah's Word and to make Allah's order prevail in the human life. Then he gets killed in this way and becomes a martyr. Jihad is necessary all the time. It is an element that walks together with the Divine Invitation."
But not ever Muslim agrees with the above. Even extremely fundamentalist Sunni Muslims disagree with the above.
Many devout Turkish Sunnis, for instance, especially those who feel nostalgic for the days of the Ottoman Empire, have a very strong anti-Wahhabi streak, and Wahhabists and other Salafists like Maududi and Qutb. Turkish publisher Hakikat Kitabevi is known for publishing books critical of all of them, with their work being a mix of theological disagreement and weird
conspiracy theories. In the book
Islam's Reformers, an extended polemic against Salafism and Salafists, states flat-out that Qutb and Maududi's version of
jihad as a revolutionary ideological struggle carried out by individuals is wrong, and (as you might expect from Muslims harking back to the days of the Ottomans) says that
jihad is strictly the purview of an Islamic Nation-State along straight-up military lines:
Well, that's all well and good, but it's still a pretty weak condemnation. Especially since the the idea of spreading Islam via conquest is still accepted by that book's authors, as well as otherwise espousing a particularly conservative brand of Sunni Islam. What do some other scholars have to say about
jihad?
Let's go back to the actual commentaries of of Qur'an. Ayatollah Sayyid Muhammad Hussein Tabataba'i, a Shia scholar who was the influential teacher of many participants in the 1979 Iranian Revolution, has a very narrow view of those specific verses in the Qur'an that Hilali and Khan say is so important in establishing the "pillar" of
jihad:
And since there aren't exactly a lot of battlin' polytheists in Mecca these days, it would seem those verses are of little applicability today (and, indeed, Tabataba'i explicitly says it does not apply to the People of the Book, ie Jews and Christians).
What about some middle ground? That is, scholars who do think the above verses give a general authority for
jihad, but not in the way the followers of Qutb and Maududi think? Well, in his own
tafsir, Muhammad Asad said:
In his book "The Road to Mecca", Asad explains this using an actual concrete example. In chapter 11, "Jihad", he talks about the family of his friend Muhammad az-Zuwayy. Az-Zuwayy's grandfather, Muhammad ibn Ali as-Sanusi, established a sort of Muslim pseudo-state in parts of what is now Libiya, recognizing the Turkish sultan as Caliph, but otherwise pretty much left to its own devices. At least, until World War I.
The
jihad against the British in World War I was not a legitimate
jihad, because the Turks were attacking the British (and the British were not "oppressing" the Muslims in such a way as to count as an aggressive act requiring defending against).
Oh, and the Yusuf Ali translation of these verses from the Qur'an? Yusuf Ali's own commentary on them says: