The liberal democratic attitude of tolerating criticism, even the most vicious and propagandistic, is what seals its own death as a system.

1. The paradox at the heart of the claim

Philosophers and analysts from Popper onward frame the problem as the paradox of tolerance: a liberal order that tolerates movements explicitly committed to destroying liberalism courts destruction of itself, a warning echoed in empirical warnings about rising illiberal parties across democracies ^{[1] [3]}. Yet the remedy is not simple: many theorists and democratic defenders argue for calibrated limits—criminalizing incitement to violence or banning parties that seek to abolish democracy—while preserving broad free expression for political contestation ^{[2] [7]}.

2. Why tolerance can become lethal in practice

Recent literature traces democratic erosion not to abstract arguments but to concrete failures of elites and institutions: democracies have often been “killed” by elected demagogues who exploited tolerant norms while dismantling informal restraints, and when party leaders abandon gatekeeping responsibilities, tolerance facilitates authoritarian conversion ^{[4] [5]}. Empirical work on legitimacy crises shows that when citizens tolerate a system only reluctantly—because they see no viable alternative—resentment and delegitimation open space for anti-system actors to capitalize on permissive public discourse ^{[8] [6]}.

3. Why unconditional suppression is also dangerous

Responses that counsel pre-emptive repression carry their own hazards: the liberal project rests on legal protections and civic pluralism that, if eroded by broad censorship or emergency powers, can produce the very illiberalism they were meant to prevent, and critics argue that failing to address underlying grievances—economic inequality, cultural dislocation—leaves repression ineffective or counterproductive ^{[9] [10]}. Comparative experiments in militant democracy (legal limits on extremist parties) show variation in outcomes: history and institutional design shape whether restrictive measures defend democracy or deepen polarization ^{[7] [11]}.

4. What the evidence suggests as a practical balance

Scholars converge on a mixed strategy: maintain strong legal prohibitions on violence and explicit anti-constitutional action, strengthen institutions and civic education to shore up democratic legitimacy, and preserve norms of mutual toleration and forbearance among political actors so that competition does not become existential combat ^{[2] [4] [12]}. The Journal of Democracy warns that failure to solve pressing problems credibly invites alternatives; thus competence, legitimacy, and responsive policy matter as much as speech rules in preventing collapse ^[6].

5. Hidden agendas and interpretive cautions in the literature

Analyses vary with intellectual and political vantage points: defenders of liberalism emphasize norms and institutional fixes ^{[4] [12]}, critics of liberalism stress cultural and economic failures that tolerance alone cannot fix ^{[9] [10]}, and some advocacy sources push for more aggressive “defensive democracy” measures—each framing prescribes different trade-offs and may underplay the risks of either permissiveness or repression ^{[7] [11]}. The available reporting cannot adjudicate which policy mix always works; it can only show recurring patterns and trade-offs across cases ^[8].

6. Bottom line

Tolerating vicious propaganda does not mechanically “seal” liberal democracy’s death, but unchecked tolerance combined with institutional failure, elite abdication, and unresolved social grievances creates fertile ground for democratic decline; conversely, heavy-handed suppression risks converting liberalism into illiberal rule—so durable defense requires targeted limits on anti-democratic violence, sustained institutional guardrails, and political remedies to restore legitimacy ^{[1] [4] [6]}.