There is nothing inevitable about liberalism.

Our form of government and political culture demand that individuals tolerate disagreements about the highest good, that the state treats all people equally under the law, that citizens resist the temptation to settle political disputes through violence, and that members of the political community forge a common heritage through a process of unending civil discussion, argument, and debate that's undertaken in a spirit of mutual respect.

All of this is extremely difficult to achieve and maintain, even in the best of times. But in periods of social, cultural, and economic stress, citizens will be especially prone to give in to illiberal temptations.

Today, the United States is passing through a particularly illiberal phase.

The illiberalism can be seen in different forms on both the right and the left. Whether it proves to be a passing trend or an early indicator of something far more ominous has yet to be determined. What's clear is that all those who cherish liberal ideals of tolerance and mutual respect need to be vigilant in speaking out against and acting to thwart these tendencies.

By far the most alarming development is the willingness of Donald Trump (but not just Trump) to deploy rhetoric and propose policies that sound an awful lot like a distinctively American form of fascism. I don't use the word lightly. It's invoked far too frequently and imprecisely in our politics. Like the proverbial boy who cried wolf, we run the risk of being dismissed for empty name calling when we use the term. But in this case it is disturbingly apt.

Consider: From the start of his presidential campaign, Trump has advocated the rounding up and forcible deportation of undocumented immigrants. How will these immigrants who lack government documentation be found? Either Trump's proposal isn't serious or he's proposing a policy that would require the use of armed agents of the state to sweep heavily Latino neighborhoods, requiring residents to produce papers proving immigration status, and then forcibly removing from homes and families those who fail to provide these documents.

That scenario is horrifying enough. But more recently, in the days since the Islamic State's terrorist attacks in Paris, Trump has pushed further — speaking openly and encouragingly about the possibility of requiring all Muslim citizens to carry religiously based identification cards, and about placing mosques under government surveillance. (Marco Rubio has since gone one step further in this direction by adding that Muslims should be monitored in any place they gather.)

Trump has also spouted blatant lies about personally witnessing thousands of "Arabs" in Jersey City, New Jersey, cheering the 9/11 attacks. And he's suggested that an African-American protester who disrupted one of his campaign rallies and was beaten by the crowd deserved to be "roughed up." (Not to be left out of the fun, Ben Carson has made his own contribution to elevating our public discourse by describing refugees fleeing the Syrian civil war as "rabid dogs.")

In its nativism and xenophobia, in its willingness to use inflammatory, demonizing rhetoric against minorities, in its deployment of demagogic lies to whip up and mobilize populist fury and whet appetites for Blackshirt-style political violence — in all of these ways, the Trump campaign (along with its opportunistic imitators) is undeniably toying with fascism, as some commentators are beginning to recognize.

And most distressingly of all, an alarmingly large number of Americans appears to approve of the organized illiberalism.

It might seem grossly unfair to compare the protesters disrupting college campuses around the country this fall to the Trump campaign, since the activists aren't running for public office and they claim to favor inclusion for those who have been historically marginalized. Yet they, too, are fundamentally illiberal in their aims and tactics.

This is not merely because the protests arise out of and make common cause with efforts to curtail freedom of speech and thinking on campuses in the name of creating "safe spaces" where people will not be exposed to contrary points of view. And neither is it simply because the goals of the protesters are often so vague that, as John McWhorter recently suggested, it's unclear whether their demands could ever truly be satisfied.

Underlying these tendencies is the illiberal conviction, which shows up again and again on campuses, that professors, staff members, administrators, journalists, and figures from the past who fail to conform to a rigidly and narrowly defined standard of moral purity should be fired, demoted, cast out, blocked, and erased from university life.

The latest and highest profile example is the push to expunge Woodrow Wilson's name and image from Princeton University — despite the fact that the 28th president of the United States also served as a historically important president of the school.

As many have pointed out, Wilson was indeed a racist whose views on African-Americans were retrograde even for his time. Yet even if we grant that institutional racism is a significant problem on contemporary college campuses, it's hard to understand how Wilson's prominence at Princeton contributes to it. Does anyone seriously believe that in 2015 even a single member of Princeton's faculty, staff, or administration walks past Wilson's name and image on campus and thinks, "I'm so proud that a racist like this once led our university"? The suggestion is absurd. Wilson is honored on campus despite his racism, not because of it.

But that, one suspects, is precisely the problem. What the protesters most want to deny is that a man with Wilson's racial views can be deserving of admiration in any respect. They hold that his racism is so toxic that it taints everything about the man and everything associated with him — including the university itself — requiring that the university deny him any form of public honor or memorial.

This puritanical drive toward a moral purge resembles nothing so much as the efforts of the most radical actors in the French Revolution to break entirely from the sins of the past so that history could be started over from scratch, with Year One. Make no mistake about it: If these Jacobin standards were consistently applied, our public life would need to be cleansed of every person in our history who fails to conform to the moral standards valorized by college-aged left-wing activists in the second decade of the 21st century. Which means that our public life would have to be cleansed of just about everyone (beginning, perhaps, with Thomas Jefferson).

That is not the liberal way.

The question all of us need to answer is whether we're willing to let it be the American way.