The term resistance seems ubiquitous today. The Democratic National Committee is offering a “Resist Trump” bumper sticker for a modest online donation (I just submitted mine). Anarchists and militant anti-fascists promote resistance to a “Trump Regime” they describe as dictatorial. Those who participated in the nationwide Women’s March or in protests opposing Trump’s Muslim ban will likely have shouted the word as part of some political chant. It can be found sprawled across the covers of both the liberal American Prospect and leftist In These Times. Even some advocates of anti-Trump consumer boycotts (L.L. Bean, for example) have placed their activities under the rubric of resistance.

Resistance now serves as a useful catch-all phrase for a diverse collection of individuals and groups outraged by our reactionary president and his allies in Congress. The term’s popularity rests on the sound shared intuition that the only way to stop Trump’s relentless Twitter-powered presidency is by no less relentless opposition to him and his allies. We need a broad, multi-pronged political movement against Trumpism. Resistance serves as a powerful rhetorical device for those working to build it.

Yet political language matters, and resistance comes with some hidden costs we need to recognize. When anarchists,as well as House Minority Leader Nancy Pelosi, start using the same category, something smells fishy.

Resistance has a long and messy genealogy. In the history of western political thought, it probably first surfaces in debates about tyrannicide, the violent removal from power of misbehaving kings who usurp authority not properly belonging to them. In the nineteenth and early twentieth centuries, anarchists and others married it to ideas of radical — and probably forceful — political and social change. (Socialists and communists, in contrast, generally preferred the term revolution, in part probably because of their adulation for 1789 and the French Revolution). More recently, the term has made appearances in an odd variety of political contexts. The French Resistance waged guerrilla warfare against the Nazis and their quislings. At mid-century, aficionados of Mahatma Gandhi and Dr. Martin Luther King, Jr. described their efforts as nonviolent resistance, a usage even today widespread among proponents of nonviolence. Reactionary southern whites, led by Virginia Senator Harry F. Byrd, infamously responded to Dr. King and others with what they dubbed massive resistance. Their idea of resistance, as we know, did not prove nearly as conscientious or nonviolent as Dr. King’s.

The term resistance has always been ambiguous. It has referred to both violent and nonviolent political action, acts aiming at a fundamental and perhaps revolutionary overhaul of existing society, and those seeking to preserve or reestablish the status quo. Revealingly, the original title of Thoreau’s famous essay, “Resistance to Civil Government,” was changed to “Civil Disobedience” by an editor who thought it too radical. For Thoreau, at any rate, resistance was an individual moral but not a collective political act. Like Thoreau, those pursuing resistance have widely been considered dangerous or at least irresponsible lawbreakers. Yet the lawbreakers themselves often saw things differently: even in medieval Europe, tyrannicide was conventionally interpreted as reinstalling a lawful and morally legitimate royal order.

The term’s present ambiguity, in short, is nothing new. That ambivalence constitutes both the source of its broad appeal — and its Achilles’ heel. It masks conflicting ideas about political strategy, and the contrasting political philosophies behind them. It also risks obscuring some tough moral and political questions.

Do you believe, for example, that the Trump Administration is already irremediably authoritarian? Some anarchists and others on the left apparently think so. That presumably is why they have few qualms about waging street battles against government representatives — in reality, low-ranking cops who need extra overtime pay. Are you instead understandably alarmed by Trump’s authoritarianism, but do not hold that the US is already an “illiberal democracy” along the lines of Orban’s Hungary or Erdogan’s Turkey? Then resistance probably should mean something else. What actions might it include? Legal as well as illegal protests? What about the perennial question of violence vs. nonviolence? Despite their anger, US progressives, quite sensibly, still pretty much universally refuse to condone violent resistance. Most would be surprised and probably alarmed to learn of the term’s prior associations with principled and sometimes violent opposition to the existing order. But what about protests resulting in damage to public or private property? If Trump were to detain Muslims or undocumented immigrants in camps or deportation centers, for example, might not “vandalism,” in some circumstances, represent a morally and politically appropriate response?

These are new versions of old questions. That is precisely my point. Recourse today to the amorphous language of resistance potentially represents a leveling and perhaps dumbing down of political thinking. Political discourse is always unavoidably messy and somewhat confusing. But too much conceptual confusion gets in the way of clear analysis and effective action.

In contrast, if we look back at the civil rights movement and anti-Vietnam War protests, we rediscover useful categorical nuances that seem to have gotten submerged in the ongoing debate about how to counter Trump. Of course, resistance then also frequently served as a broad category meant to express principled opposition, for example, to the war in Vietnam, or to a capitalist order many on the New Left came to despise. Yet activists also made some finer distinctions. For example, some described what they were doing as direct action, meaning protest beyond the usual corridors of power and transcending the conventional methods of shaping decisions in them. Either legal or illegal, direct action ideally entailed a dramatization of some injustice, as well as an immediate, tangible grassroots effort to contravene it. Since political lawbreaking could also take different forms, nonviolent civil disobedience was widely distinguished from violent resistance or revolution. The former contributed to reform, whereas the latter sought to replace the existing order altogether. (A distinction further complicated by the radical reformism of Dr. King and others, who embraced nonviolent civil disobedience partly because they deemed it more conducive than political violence to lasting, radical change. For King, civil disobedience was a peaceful yet transformative political tool). Civil disobedience and violent resistance or revolution, at any rate, both differed from conscientious objection, resting on moral conscience and justifying an individual’s noncompliance with the law.

With the civil rights movement in mind, the liberal philosopher John Rawls argued that civil disobedience was appropriate to “nearly just” societies, meaning ones in which basic liberal and democratic mechanisms continued to operate, notwithstanding egregious injustices (for Rawls, racial segregation) that required correction. Civil disobedience aimed primarily to persuade political majorities complicit in injustice to change their minds and support the requisite shifts in law and policy. It presupposed a real possibility that the politically disadvantaged could rely on nonviolent lawbreaking to sway the presently advantaged and eventually generate meaningful political reform. Violence especially against persons was unacceptable, Rawls believed, because it conflicted with the basic respect we owe each other as equal citizens. Rawls never denied the possible legitimacy of more militant or violent resistance: he just thought it inappropriate in a more-or-less well functioning liberal democracy.

If Donald Trump gets away with making mincemeat of our democracy and its constitutional pillars, those of us who oppose him will need to have a serious conversation about resistance in the exacting sense employed by Rawls and others. Trump, in effect, would have unambiguously resolved the controversial matter, long debated by philosophers and political theorists, of whether the US deserves to be described as a “basically just” and sufficiently liberal democratic order.

At any rate, resistance — defined as potentially violent fundamental opposition to the existing order — raises difficult moral and political questions by and large spared those of us who presently believe the best way to stop Trump is by some combination of grassroots popular mobilization, principled nonviolent lawbreaking, and old-fashioned institutional (including electoral) pressure. When smartly practiced, civil disobedience can help guard our democracy from Trump and his billionaire buddies, just as it once helped King guarantee voting rights to African Americans. Conscientious objection can do so as well: if conscientious officials refuse to abide the many onerous and probably unconstitutional Trumpist measures sure to come, they may be able to gain the moral and political upper hand.

Its wide appeal notwithstanding, the term resistance masks sizable political differences and potentially sows confusion. Like previous generations of political progressives, we will need a somewhat more refined and subtle political language if we are to ward off the terrible threat our democracy now faces.