"What would be your guesstimates?"
To estimate actual fighters across dozens of organizations across dozens of countries, then add on "fixers and facilitators", then add even more low level supporters, is (IMO) to pull a number out of a hat. But, no, I don't think your estimate that one-tenth of one percent of worldwide Muslims (a million out of over a billion) is "seriously intent on destruction of all infidels " (encompassing all categories described above) is inflated. Neither do I have a problem with your second guess that another quarter to half percent of all Muslims worldwide might feel strongly enough about one of the dozens of struggles that they would write a check, provide shelter, or otherwise give some indirect support.
But if we conclude that the other 99.75% of Muslims are "the enemy" (despite the fact they have done nothing so far to deserve that title except for the fact they happen to be Muslim - - and that they mostly don't like us - - but neither do most of our "friends" at the moment), because we conclude that their religion is irredeemably violent (which does not explain why less than 1% are actually engaged in jihad), then this becomes not a war against "jihadis" or "militant Islam" or "political Islam", but a war against just plain Islam, then the other 99.75% of the one billion will perceive themselves as being under actual or imminent attack, and they will respond accordingly.
It would make more sense to unilaterally declare war on China. At least those billion are not spread over some 60 countries and not susceptible to a martyrdom ideology with WMD as the weapon of choice.
The war is for the hearts and minds of the 99.75%. The trigger-pulling with the .25% (without denigrating the heroism and sacrifice of those who are fighting that very lethal segment) is, at least relatively speaking, in the great scheme of things, a sideshow.
That is why the "prisoner abuse/torture/systematic homicides/officially sanctioned atrocities" was without question, the most damaging blow ever to hit America. More damaging than Pearl Harbor and more damaging than 9/11.
And we did it to ourselves.
They didn't "miscalculate" on 9/11. They *knew* we would respond. They were hoping we would go into Muslim countries and out of blind rage just tear the places apart. What are they trying to do in Saudi? Attack the oil so the world gets its oil spigot turned off and force us all to descend on Mecca (proving their point that there really *is* a holy war going on against all Islam)
Why are they trying as we speak to pull off a WMD attack in the US? So we will be enraged to the point that we fulfill their prophecy and go over there with a blind, nuclear rage and send their women and children straight to Allah. The militants are that sick. (Look at the picture of the baby with the gun) They are baiting us into giving them mass martyrdom, turning the 99.75% to unrestrained holy war, and giving them the apocalyptic clash of civilizations they want.
The unfolding torture and abuse has done more to validate al Qaeda's rantings that we are intent on a crusader conquest of occupation, exploitation, and humiliation than anything we could have imagined in our wildest nightmares.
This war is not just about bullets and bombs. It is primarily about ideas - - hearts and minds. If we win the battle but lose the war, it will not matter. If we equate Islam with jihad, then we have handed the jihadis a strategic victory. That is what they have been trying to convince the one billion for a decade now. And legitimating their ideology by giving them the holy war they want will take them from their caves and basements to the parliaments and palaces of the region. And they will fund global jihad not with donations from sympathizers, but with the world's energy under their feet. And if we retaliate with WMD on one of our cities with WMD in spades on theirs, then we will not have a million holy warriors, but one thousand times more.
Why are they trying so hard to get WMD and use it on us? If we don't understand the strategy of the enemy, then we will lose.
If we don't somehow get the central point of WMD and holy war, then speaking as someone who knows a little bit about what I am talking about, we are finished.
Finished.
A GREAT DEAL of wisdom in your post.
I would that it be posted on billboards far and wide.
Alas, what is your prescription?
It seems we have few attractive options.
The million plus are not going to give up trying to incite us as well as the rest of their coreligionists . . . short of . . . most probably . . . death.
Changing their minds is as likely as finding each of them and executing them . . . . bloody unlikely to impossible.
Therefore?
Well said.