What motivates these jihadists who attack innocents, as in Nice?

In a complicated global war like jihad, there are many motives. 

However, here is the main one that is embodied in these verses: Islam must dominate all other religions.

61:9 He it is Who has sent His Messenger (Muhammad) with guidance and the religion of truth (Islamic monotheism) to make it victorious over all (other) religions even though the Mushrikûn (polytheists, pagans, idolaters, and disbelievers in the Oneness of Allah and His Messenger Muhammad) hate (it). (Hilali and Khan, The Noble Qur’an, Riyadh: Darussalam, 1996)

And for good measure, it's repeated, almost word for word:

48:28 He it is Who has sent His Messenger (Muhammad) with guidance and the religion of truth (Islam), that He may make it (Islam) superior to all religions. And All-Sufficient is Allah as a Witness. (Hilali and Khan, parenthetical notes are theirs)

Again:

9:33 It is He Who has sent His Messenger (Muhammad) with guidance and the religion of truth, to make it superior over all religions, though the Mushrikûn (polytheists, pagans, idolaters, disbelievers in the Oneness of Allah) hate (it). (Hilali and Khan, parenthetical notes are theirs)

It's the latter verse that is the most troubling because it appears in Chapter 9, the last chapter to be revealed.  It comes in this violent context:

9:29-30 Fight [q-t-l] against those who (1) believe not in Allah, (2) nor in the Last Day, (3) nor forbid that which has been forbidden by Allah and His Messenger (Muhammad), (4) and those who acknowledge not the religion of truth (i.e. Islam) among the people of the Scripture (Jews and Christians) until they pay the Jizyah with willing submission, and feel themselves subdued. 9:30 ... [A]nd the Christians say: Messiah is the son of Allah. . . . Allah’s Curse be on them, how they are deluded away from the truth! (Hilali and Khan, parenthetical notes are theirs)

The Arab root q-t-l is the basis of the word qital, and it means only military warfare or killing or fighting, not a quest to wage inner or "lesser" jihad or struggle against the vices in one's soul. 

The historical context of the verses is as follows: In 630 A.D., Muhammad led an army of 20,000 jihadists up north to confront the Byzantines because he had heard a rumor that they were amassing an army to attack.  The rumor was false, but on his travels north, he met various Jewish and Christian tribes.  He had the upper hand and was superior in numbers.  So he conveniently got a "revelation" that is expressed in 9:29-30.  Jews and Christians have to pay a tax and keep their religion, or convert, or keep fighting and die. 

Islamic armies have been following his example ever since.

You can read the verses in four orthodox Sunni translations at quranbrowser.com and type in the references.  

Islam must prevail over all other religions, even if that means qital.

So how do we apply these verses to the recent events and the political landscape?

It is customary to say that the sooner we understand Islam, even the one offered in the Quran, and say the words "radical Islam and Muslims," the sooner we can defeat them.  That's true.  Yet the president recently said in a press conference that saying the words does not amount to a strategy.  That's also true, except no one claimed that it was a strategy.  Instead, it is the first step that reassures the home front that the president understands the enemy.  Imagine if President Roosevelt avoided saying the word "Nazi" for fear that more Germans might join the Nazi military, for example, and then criticized his opponents who urged him to say the word.

So let's revise the standard ending of a post like this and instead say that the sooner the left understands Islam, the more clearly and loudly the left can proclaim that Islam itself has a warped and sick ideology at its very core and in its very origins.  ISIS understands it and obeys it.

The sooner the left can tell the handful of moderates out of a billion-plus Muslims that they must stop withholding the unpleasant side of Islam when they claim that the Quran doesn't say what we all know it does. 

The sooner the left can demand that these moderates admit that Islam must be abandoned or radically reformed (if that's possible).

The sooner the left can demand that Muslim leaders renounce major chunks of sharia and affirm that a seventh-century, culture-bound law in many aspects is wrong and misguided – though simple parts do no harm, like washing before entering a mosque or not eating pork. 

The sooner the left can understand that many parts of sharia are incompatible with American values.

The sooner the left can demand that all the imams who don't preach violence, like the one in my neighborhood, must rise up and report suspicious activities.

Will the left do this?  Of course not.  Those questions were rhetorical.  It's in the left's nature to misunderstand world events. 

And so the administration's and Hillary's weakness keeps on endangering us. 

The sooner we vote the left out of the capitals around the world and vote in sensible leaders, the safer we'll be.

James Arlandson's website is Live as Free People, where he has posted Islamic Martyrdom: The Economy of Death in the Quran, A Brief History of War in Earliest Islam, Stop Calling Us 'Islamophobes"!, Are Islam and Christianity Equally Violent?, the Truth about Islamic Jihad and Imperialism: A Timeline, How to Reinterpret the Quran, and Jihad and Qital in the Quran, Traditions and Classical Law.