There is no need to debate with the Salafi/Wahhabis on ideological grounds. It's their history that condemns them most effectively. Until now, it had been difficult to get precise details on Saudi history. However, I read an excellent book recently by David Cummins, called the Wahhabi Mission and Saudi Arabia. It is the only comprehensive study of the history of SA and Wahhabism that I know of.
In any case, it's nearly impossible to pin the Salafi down on any one particular principle. They have mastered the ability of denying everything and blaming any wayward ideas on false representatives of their movement.
They will usually even deny that they are "Wahhabis" and or that any such name even means anything. And yet, they follow closely the reformation proposed by Abdul Wahhab
This is what is sneaky about this group. They basically insinuate themselves as merely a devout segment of the general Muslim population.
But, a reading of their history reveals very clearly that they are most definitely a sect, and have deviated from the body of the Muslim population since their founder.
This is the fact that becomes very clear in reading the book. It also helps to explain a lot about the Wahhabis and their ignorance, as well as their political inclinations.
Because, from the beginning, the relationship between the Saudis and Wahhabis has been one of tacit compromise. Monarchism, we know, is an affront to traditional Islamic practice. But from the beginning, the Wahhabi clerics agreed to overlook the ruler's poor implementation of Islamic law, as long as they could continue to concentrate on "reforming" the masses. This is of course egregious hypocrisy, but it helps to explain the relationship that persists into our time.
What I try to point out in my book is that what the world has completely failed to recognize is that the real "axis of evil" is Britain, the US and Saudi Arabia. And that SA has not only played a pivotal role in the conspiring of the last half of the 20th century, but has been a willing participant, in what is evidently a long-term strategy against the Islamic world, or all part of the creation of a "Clash of Civilizations", between Islam and the West.
So SA is in blatant collusion with the enemies of Islam in an attempt to undermine it. And much of the Muslim world is completely unaware of that, due primarily to the massive propaganda campaign that the state has maintained over the century, through the monopolization of Islamic literature.
But that is only part of the problem. The central aspect of this problem is the fact of that the so-called "Ulema" are a state-sponsored religious establishment (likely the only one of its kind in the world). So throughout the century they have acted to excuse the actions of the ruling family.
This explains the narrow conception of Islam that they propagate. Because they are not able to address the guts of the matter, which is the corruption of the royals, they have to compensate to by trying to appear strict in other less substantial matters. But the contradiction is that, and as controversial as this may sound, Islam is a political ideology. It's a complete system of politics, offering an alternative to capitalism, communism or anarchism. The more trivial details were never meant to be emphasized to the extent they are by the Wahhabis.
This is how they fail to communicate the true meaning of Islam. I would say this is the reason why the Muslim world as a whole is plagued with hypocrisy. Ask a Muslim what Islam is, and he will list you the "five pillars", but he doesn't understand the political responsibilities that it imparts to him, and that are the true essence of the religion.
This is compounded by another fact. Essentially, Wahhab denounced the Islamic world, except for his small band of followers, as "Kaffirs", or apostates, who had fallen outside of Islam, and therefore that it was legal to fight and kill them and seize their property, and enslave their women and children. Conveniently, the modern Wahhabis never refer to this aspect of their history.
And, to protect their ignorant citizenry from learning the true Islam from other parts of the world, they produced prohibitions against fraternizing with the "infidels". They managed to keep this quarantine on the country essentially ever since. Through this exclusion, and by rejecting traditional Islamic scholarship, they have created a manner of dialogue on Islamic jurisprudence that is completely unique to themselves.
The problem is that the Muslim world is unaware of that. Because when the Wahhabis say "this scholar said" or "that scholar said...", they are not referring to the centuries of Islamic legal opinion, but to their own Wahhabi tradition. However, Islamic legal thought had developed strict processes for formulating opinions. The development of several schools is testament to the tolerance that was perceived necessary in the interpretation of such laws. While the Wahhabis, on the contrary, do not have to resort to precedence, or support their arguments by past decisions, and are therefore free to distort the religion at their whim.
For all these reasons, SA has a completely unique but also very narrow and chauvinistic interpretation of Islam, which, however, they have been able to, through their fantastic oil wealth, spread to much of the Muslim world. I hope that studies like The Hijacking of British Islam: How extremist literature is subverting Britain’s mosques will help elucidate that the current conception being propagated is one that is being monopolized by a single voice, but more importantly, that that voice comes from a very minor and corrupted sect of Islam.