TrumpTodd Kranin / ReasonSome of Donald Trump's most ardent supporters believe he is the only candidate who will defend Western culture from its enemies both foreign (illegal immigrants, Muslims) and domestic (cultural relativists, campus leftists). The U.S. is besieged by forces that want to destroy its cultural heritage, and Trump is the only one who gets that, they say. 
This is a terrible reason to support Trump, but not because the values of the West aren't worth protecting—they are. The sad! fact is that Trump adamantly rejects two of the most important legacies of the Enlightenment and Western society: free markets and freedom of the press. No presidential candidate who fails to grasp why unrestricted trade across national borders is the hallmark of a civilized society is fit to lead one, and no leader who seeks the power to shut down newspapers who criticize him can be trusted to defend classical liberalism from its enemies. 
Over at The Federalist, Mytheos Holt makes the most straightforward case that Trump is the candidate for a nation at war with the forces of barbarity and economic decline: 
Donald Trump deserves to be president. More than any of the current candidates—although not to their exclusion—he is the best choice to lead this nation. … 
Trump, whatever else he might be, is unabashedly pro-Western. What’s more, he understands the essentially cultural and even spiritual nature of the vacuum white nationalism fills. 
White nationalists, in Holt's view, are misguided to the extent that they put undue importance on race. It's the values of Western Europeans, not their skin color, that matters: 
… The sorts of people who are attracted to white nationalism are people whose own communities have been hollowed out by economic and cultural forces beyond their control, and who are now adrift in a society they perceive to be universally hostile to their heritage for no good reason. 
That heritage, as white nationalists in America see it, is the heritage of Western civilization. If you wonder what that means (which is reasonable), let me spell it out: It means historically Western European cultural norms. Specifically, norms like respect for agents of the law, aspirational pride in work, willingness to accept the consequences of one’s actions, disdain for laziness and welfarism, and reproductive responsibility (i.e., not having children you can’t afford to keep). 
They respect these norms not merely because these are what their own communities follow, but also because they think these norms make constitutional government, liberty, and classical republicanism possible. 
I agree with Holt that Western civilization is responsible for a lot of good in the world (and some bad, naturally). But I disagree emphatically that Trump has any standing to claim that he is "unabashedly pro-Western." A man cannot portray himself as the defender of the Enlightenment, modern Western civilization, and classical liberalism if he is desperate to undo its crowning achievements. 
And make no mistake, Trump and Western culture are oil and water. His illiberal, uncivil tendencies are too numerous to list here, but for starters, he has vowed to make it easier to sue newspapers. His staffers assault journalists. His supporters attack protesters. This is not a man who believes, as the 18th century French philosopher Voltaire did, "I disagree with what you say, but will defend to the death your right to say it." This is a man who wants to silence his critics and thinks the government is just one tool for accomplishing that. 
Trump is also totally opposed to free trade—a natural extension of the right to free expression, and the cause of Western nations' rapid increase in prosperity over the course of the last two centuries. Trump would do everything he could to rid the U.S. of the economic conditions that made it rich in the first place. 
Trump is only "unabashedly pro-Western" in the sense that he wants the U.S. to replicate the pre-Enlightenment conditions of Western Europe: the Dark Ages. Of course, there's nothing particularly Western about the Dark Ages—the entire world has suffered some version of the West's long period of tribal warfare, poverty, and repression. 
Since Trump is not actually someone who defends Western values, it seems like the more obvious explanation for his popularity is the better one. Trump is not the candidate of Western European values: he is the candidate of people who descend from Western Europeans—white people. He excites racists, not because he appreciates modern civilization, but because he appeals to racism. I agree with The Federalist's Robert Tracinski, who writes that members of the so-called alt-right—Trump's online fanbase—"are just a bunch of racists": 
I can’t find anything particularly “right-wing” about them—not in the American sense, which has traditionally meant advocacy of free markets, individual rights, and the ideals of our Founding Fathers. ... 
The central theme of the Western intellectual tradition is about rising above tribalism to arrive at universal values. That’s a common theme that connects both secular and Christian traditions in the West. It was the whole distinctive idea behind the Ancient Greek revolution in thought. Philosophers like Socrates launched the Western tradition by asking probing questions that were meant to sort out which ideas and practices are based merely on historical accident and social convention, versus those that are based on universal laws of human nature. ... 
The fact that much of the alt-right is ignorant of the Western tradition was made clear to me by those who insist that Hispanic immigrants are culturally “non-Western” and “non-European.” They are apparently unaware that “Hispanic” refers to the linguistic and cultural influence of Spain, which is in—anyone? anyone?—Western Europe. So much for caring about the cultural legacy of the West. 
Need more reasons to hate Trump? We've got you covered. [Related: The Incredible Cluelessness of Donald Trump]