I've come across a blog called "Race Files" run by a guy named Scot Nakagawa whose commentaries are typically very insightful. In one of his posts from this past May titled "Blackness Is The Fulcrum", Nakagawa explains how and why his activism has become focused on anti-Black racism even though as an Asian man he might almost certainly have enough material to explore racism in depth.
As he explains, his reason is simple......
So why do I expend so much effort on lifting up the oppression of black people? Because anti-black racism is the fulcrum of white supremacy......A fulcrum is defined by Merriam-Webster asor, alternatively, “ In other words, if you want to move something, you need a pry bar and some leverage, and what gives you leverage is the fulcrum – that thing you use so the pry bar works like a see-saw.He goes on to describe the conditions of under-privilege, institutional racism, and inequality that has come to define the experience of black America. What is most strange about this post is that it is so correct on so many points, yet, I think that Nakagawa is actually mistaken in his conclusions that anti-black racism is what supplies the capability for action. Given the extreme abuse and prejudice that Africans, and African-Americans have experienced over the past few centuries, this might seem like a strange thing to say. Yet, if we examine history we can easily see that white supremacy predates America and that whatever forces contributed to the development of the racialized society that characterizes America's past and present, anti-black racism fails as an explanation for it.
Furthermore, white supremacy underlines almost every modern day inequality that we see around the world today - both within the US amongst its ethnic groups, as well as across the world as reflected in the variance in rates of poverty, wealth and power distribution, and political instability, that exists between the white countries and the nations whom they formerly colonized. The modern world with all of its racially delineated inequalities emerged out of the West's imperial meddling. So, claiming that America's anti-black racism provides the capability for the action that is the foundation of white supremacy is, thus, the same as saying that anti-black racism is what drove the European nations to embark on the imperial activities which led to the racial hierarchies that exist in the world today both between ethnic groups in the US and internationally in the power inequalities between nations. In other words,what this means is that implicit in Nakagawa's claim is the notion that anti-black racism was the driving force behind western imperialism because the structures of modern day racism and the white supremacy that upholds it were all established in this period.
Awkwardly, the historical record refuses to co-operate with this notion. The established fact is that Asia was colonized centuries before Europe even considered colonizing Africa. For at least the first two centuries of European colonialism Africa was simply an obstacle to sail around, and was largely ignored. Europe's oldest colonies were in The Phillipines, Macau, Indonesia, Hong Kong, and India - granted, Europeans established coastal forts along the coast of Africa, but these served largely to foster the movement of goods and people stolen or traded from the Asian colonies. So, why would the white supremacy that drove European imperialism ignore Africa if these notions of white supremacy were based on anti-black racism? The answer is that anti-black racism is not the foundation of white supremacist thinking and, therefore, cannot be the foundation of white supremacy.
Understanding what drove Europeans (and later, Americans) to wage centuries-long wars of aggression against the unsuspecting peoples of Asia, The Americas, and Africa, is really the only way to understand white supremacy and how it came to be the dominant characteristic of the global world order. But what has to be understood most of all, is that the West's war against non-white peoples began with an assault on Asia.
Throughout the Medieval period as trade between Asia and Europe grew, commodities like silk and spices became highly prized in Europe (as they had been since ancient times) and the wealth that was generated was coveted by European merchants and kings who set about to find ways to control this trade. Thus, the objective of the first wave of imperialism was to gain control of these prized markets by coercion, conquest, and enslavement - when Columbus "discovered" America he was on his his way to find a route to Asia to do this exact thing.
Yet, the background to this lies in antiquity. Ever since the age of classical Greece, the power and wealth of Asia has been feared and envied by the West and it is ideas of influential classical Greek thinkers that formed the basis for justification for the European right to rule, which evolved over the centuries into the justification for the right (and necessity) to colonize, and which ultimately became the basis for the racial hierarchy of white supremacy. As far back as the 5th Century BC, thinkers like Hippocrates, and Aristotle began to formulate concepts of race and racial differences between the peoples that they encountered which placed Greeks firmly at the top of a racial hierarchy. According to Aristotle "Asiatics" were servile and suited to being ruled because they endured tyranny without challenging it.......
The power possessed by all of these [non-Greek Kingships] resembles that of tyrannies, but they govern according to law and are hereditary;  for because the barbarians are more servile in their nature than the Greeks, and the Asiatics than the Europeans, they endure despotic rule without any resentment. ....[Link]And here......
The peoples of Asia on the other hand are intelligent and skillful in temperament, but lack spirit, so that they are in continuous subjection and slavery. But the Greek race participates in both characters, just as it occupies the middle position geographically, for it is both spirited and intelligent......Hippocrates goes a step further, and in his writings we should note some very familiar stereotypes.....
I say, then, that Asia differs very much from Europe as to the nature of all things, both With regard to the productions of the earth and the inhabitants, for everything is produced much more beautiful and large in Asia; the country is milder, and the dispositions of the inhabitants also are more gentle and affectionate.Aww, how sweet! But then.....
Manly courage, endurance of suffering, laborious enterprise, and high spirit, could not be produced in such a state of things either among the native inhabitants [of Asia].....Oh.
But here, we learn Hippocrates' true feelings.....
with regard to the pusillanimity and cowardice of the inhabitants, the principal reason the Asiatics are more unwarlike and of gentler disposition than the Europeans is ......the Asiatic race is feeble, and further, owing to their laws; for monarchy prevails in the greater part of Asia, and where men are not their own masters nor independent, but are the slaves of others......So, already we can see that several concepts about race are taking shape; an implied "nobility" of Greek (European) nature (white superiority), the superiority of Greek socio-political systems, it is in the nature of Asiatics (and other non-Greeks) to be subservient (inferiority of Asians), and that the Greek nature lies perfectly at the middle of two extremes between Asiatics and Barbarians - that is, both intelligent and physically powerful (compare to modern day Race Realists who proclaim the white race to be at the perfect middle of the racial extremes of black physicality and Asian intelligence). It should also be noted that for the Greeks (and later the Romans) climate was a major factor in determining the racial characteristics of various peoples - this is important in establishing the continuity of these ancient stereotypes up to the present. So right here, we can see ideas taking shape that can be described as some kind of primitive white supremacy.
It has to be noted that these ideas about Asia referred to the peoples of the Persian empire, but this idea of an ominous East populated by a cultured but intrinsically different (and inferior) people who pose an existential threat to the ideals of Western freedom, is a notion that echoes loud and clear up to the present day. Following the Greeks, the ancient Romans also viewed Asia with suspicion and envy. To them it was a land populated by morally inferior people, whose influence on the integrated Roman populace could only be negative. Throughout western history these ideas have resurfaced in one form or another such that a continuity of racialized thinking originating with Europe's earliest philosophers and carried forward to today is almost undeniable.
Throughout the medieval period the works of ancient Greek thinkers resurfaced amongst Christian theologians, and Aristotle's "Politics" (from which the first two quotes above are taken) was translated into Latin in the 12th century and became very influential in Catholic philosophy which some believe contributed to legitimizing Europe's slave trade. From the Middle Ages onwards, study of the ancient Greek thinkers (like Hippocrates and in particular Aristotle) was integral to education in Europe and it has been suggested that this rediscovery of ancient philosophy drove the Renaissance. It is unsurprising, then that later on still, we see many of these ancient concepts of race and the right to rule surfacing in the work of early race scientists who expanded on these ideas first formulated by the Greeks. Although "scientific" racism vastly expanded the scope of racist thinking, it is not hard to find similar threads of thought that echo these ancient concepts. Racial physiognomy, the notion that climate is a determinant of racial characteristics, as well as reiterations of centuries old stereotypes, are all to be found in the writings of scientific racist literature of this time.
It seems clear then that the modern concept and practice of white supremacy has a history pre-dating anti-black racism, and that the idea of European (white) superiority and the right to rule has its roots in the writings of ancient Greek thinkers. Underlying many of the most influential of these writings is an implicit theme of the "East" presenting an existential threat to the West, and it is this East/West conflict that has come to underscore the character of the modern geopolitical world. It is primarily against Asian culture and civilization that Greek thinkers measured the superiority of their own civilization and racial characteristics, and by so doing, asserted their right to rule. And this is important for several reasons.
This idea of an East/West conflict is the one theme that carries forward from ancient times to the present. From the days of classical Greece whose civilization faced an existential threat from Persia (remember also that Alexander the Great was a pupil of Aristotle), through to the first wave of European imperialism that sought to monopolize East/West trade through conquest, and on up to the present time of Muslim/western conflicts and economic conflicts with far Eastern countries, it is this idea of a heroic West locked in existential combat with a barbaric and menacing East that underlies the identity of Western civilization - it is by way of comparison to civilizations of the East that the West has been found to be superior. Hand-in-hand with this is the notion of a racially inadequate Asiatic whose subservient nature makes him unsuitable for little more than servitude. Clearly, the idea of servile Asiatics whose subservience justifies European rule, is a concept that has survived through the ages as successive generations of Western thinkers have studied the works of their predecessors all the way back to ancient Greece.
Given all of this, it seems short-sighted to claim that anti-black racism is the fulcrum (foundation) of white supremacy. The white supremacist thinking that drove Europeans in the 15th century to claim the right to own Asian lands and people derives from a separate philosophy of racism over two-thousand years in the making that exists regardless of Western attitudes towards Africans. In fact, some of the earliest black slaves were carried to China (and worked alongside Chinese slaves) by the Portuguese to develope and exploit stolen lands. Thus, in some ways and some instances, it is more accurate to say that the enslavement of Africans (and the subsequent "scientific and religious justifications thereof) is a by-product of the philosophical tradition that sought to justify the European's right to rule over Asia and which forms a fundamental aspect of the Western identity as a superior entity to civilizations of the East.
Not recognizing this history only upholds white supremacy. Given that one of the major geopolitical themes we see recurring over the past several decades has been this struggle of Western economies to maintain their hegemony over upstart East Asian nations, whose economic prowess challenges the very basis of white power. The West's shrill, fear-mongering, concerning Asian economies seems to view Asian economic prosperity (that is an Asian middle-class who can afford TVs and cars) as an affront to their identities and a threat to their survival, and is a modern day manifestation of this centuries-old way of thinking about the "rightful" world order which has whites at the top and everyone else below in no preferable order. This notion that there is an existential East/West conflict is one of the drivers of the suppression of minorities in Western countries - those who are excluded from the upper echelons of the racial hierarchy pose a threat to it and thus, to ignore the history of this philosophy and its present-day manifestations handicaps the fight against racism.
In summary, although anti-black racism has been persistent, it can only be said to tell a portion of the story of how white supremacy came to dominate the thinking and attitudes of western cultures. Clearly, the role of what ancient Greek and successive European thinkers came to view as an existentially significant East/West struggle that spawned twenty-five hundred year-old racial stereotypes about Asian people, as well as the notion of the right to conquer and rule, forms a substantial portion of the foundation of white supremacy. Without it, history and the modern world may well have been considerably more egalitarian.