I read a short news piece recently remarking on the reemergence of polio. Those of us over seventy who grew up in the fifties remember how terrifying the disease was. Tours of iron lung trailers (trucks pulling trailers containing children who could not breathe without mechanical assistance, only their heads emerging from the edge of the iron lung) were common and reinforced the general fear. Polio, for those born after the development of the miraculous vaccines [1], is a crippling, incurable, very contagious disease that can affect people in a variety of ways. " It can cause acute muscle paralysis, permanent central nervous system damage, and even death. As per the World Health Organization (WHO), death occurs in about 5–10% of patients who become permanently paralyzed due to immobilization of their breathing muscles. [2] Thanks to routine vaccination now of children, the disease has been wiped out in the United States -- until 2022 when it was confirmed "On July 21, 2022, the USA witnessed the first case of poliomyelitis after nearly 3 decades of its eradication." [2]
The recent outbreaks of measles, another of those insidious diseases that can kill or have long-term effects, thanks to stupid parents who don't get their kids vaccinated, and our recent experience with COVID trypanophobia, not to mention the evidence of long-COVID in the president, I was emboldened to do some digging into the effects of plagues and other diseases on political systems.
One major event was the Antonine Plague, otherwise known as Galen's Plague, which appears to have been either typhoid or a smallpox variant. (Smallpox being another disease wiped out world-wide thanks to vaccinations, it holds no terrors for stupid modern people.)
The Antonine Plague (approx. 165–180 AD) was a devastating pandemic that struck the Roman Empire during the reign of Marcus Aurelius. It has been estimated to have killed up to 5 million people (roughly 10% of the population), severely weakened the army, and presaged decline of the Empire. The plague was likely introduced by soldiers returning from campaigns in Seleucia (Mesopotamia). It spread throughout the empire, from the Near East to the Rhine frontier. Galen described the symptoms in detail: fever, diarrhea, sore throat, vomiting, and black-pustule skin eruptions. The mortality rate was estimated at 25%, with up to 3,000 people dying daily at its peak. (Note that the CDC estimates Covid affected 70+% of Americans. [3]) It devastated the army, the aristocracy, and the economy. The emperor himself was affected by the plague in 164–165 AD and died in 180 AD, likely of the same disease, while campaigning. The plague is considered a key factor in the beginning of the decline of the Roman Empire.
Epidemics are often remembered for their mortality. Historians and political scientists increasingly argue that they also change politics. Epidemics create labor shortages, which give ordinary people more bargaining power. They weaken trust in rulers who fail to protect their people. Under the right conditions, these pressures have pushed societies toward more inclusive and democratic institutions.
The most direct economic effect of a severe epidemic is a sudden drop in the number of workers. Denemark [5] finds that across history, pandemics have tended to increase class conflict, and that "labour shortages generate wage pressures" in a cycle that can last several generations. When fewer people are available to farm the land or work in towns, surviving workers can demand more, and elites who depend on their labor must either pay more or use force to hold on to them.
Gingerich and Vogler build their argument on this idea. They contend that a pandemic can influence politics in the long run if the loss of life is high enough "to increase the price of labor relative to other factors of production" . The Black Death of 1347–1351 created exactly this kind of shock. As Gingerich explained in an interview about the research, the plague sharply reduced the agricultural labor force in the hardest-hit parts of German-speaking Europe. Surviving laborers could negotiate higher wages from competing lords or move to areas that paid better, and the resulting rise in wages and living standards helped erode serfdom
The response of elites mattered a great deal. Where mortality was lower, landowners could deal with milder labor shortages by "doubling down on coercion" and keeping serfdom in place longer The size of the shock therefore helped decide whether workers gained real leverage or whether the old system survived.
Epidemics test governments. When rulers cannot protect their people or provide for them during a crisis, their claim to authority can weaken. In other words, people who suffered from disease and hardship became less willing to accept the authority of the state. That loss of trust did not automatically turn into organized resistance. . Pandemics affect states unevenly: "capable political units" grow stronger, while weak ones suffer retrenchment [5]). A government that handles an epidemic poorly may lose both public confidence and real power.
The Black Death study shows how these economic and political shifts could, over time, support democracy. Gingerich and Vogler argue that when labor-repressive systems such as serfdom become untenable, the result is "the development of proto-democratic institutions and associated political cultures that shape modalities of political engagement for generations" [6]. Their evidence is striking. Areas hit hardest by the plague were more likely to adopt inclusive political institutions and more equal patterns of landownership. Centuries later, voters in those areas showed more independence from landed elites, and in the Weimar Republic's 1930 and July 1932 elections they gave significantly lower vote shares to Hitler's National Socialist Party [6]
As Gingerich put it, workers who gained more freedom in the economic sphere "also found more freedom in the political sphere," because previously disadvantaged groups had gained greater bargaining power. Vogler adds that participatory elections at the town level appeared in heavily affected areas to some extent even before the Protestant Reformation . By contrast, less affected regions kept unequal landownership and elite-dominated politics into the nineteenth century. Those areas also saw more electoral disputes involving fraud or intimidation 8
Studies show that epidemics can reshape political systems by changing who holds power. Labor shortages strengthen workers against elites, and failed government responses erode legitimacy. But the outcomes differ widely. In late medieval Germany, a severe demographic shock helped break serfdom and laid the foundations for more inclusive politics. Denemark's long view helps reconcile these cases: pandemics reward capable states, weaken fragile ones, and intensify class conflict . Whether an epidemic leads toward democracy depends on how severe it is, how elites respond, and whether ordinary people have the leverage and the organizations to turn their grievances into lasting political change.
The United States has not been immune. Yellow fever altered American history through its connection to the transatlantic slave trade, whose ships carried the virus and the mosquitoes that spread it from Africa to the Americas. In Saint-Domingue, now Haiti, the disease devastated the French army sent to crush the revolution and restore slavery, helping Haitian revolutionaries defeat Napoleon’s forces. This defeat undermined Napoleon’s plans for an American empire, in which Louisiana would supply provisions to France’s Caribbean colony, and helped persuade him to sell the Louisiana Territory to the United States in 1803. The resulting Louisiana Purchase roughly doubled the nation’s size, opening vast territory to U.S. expansion. Thus, a disease spread through the slave trade helped undermine France’s colonial ambitions and reshape the United States. [7]
The Spanish Flu had similar effects. It disrupted the 1918 midterm elections and provoked disputes over government authority. Restrictions on public gatherings curtailed rallies and speeches, while illness and fear of infection complicated voting; turnout was unusually low, although the pandemic’s influence is difficult to separate from that of World War I. Republicans won control of both houses of Congress, weakening President Woodrow Wilson, but historians cannot confidently attribute their victory to influenza rather than wartime controversies and other political issues. Public-health measures also sparked organized opposition, notably San Francisco’s Anti-Mask League, which protested compulsory masking in January 1919 and challenged local officials over individual liberty and government power. The pandemic’s clearest political effects were therefore disrupted campaigning and voting, along with conflict over public-health authority—not a demonstrable nationwide shift toward one party. [9]
Should another major epidemic hit the United States, assuming widespread fear of vaccination continues and multiple deaths occur, we would see increased polarization, strained institutions, and continued reshaping of party coalitions. History reveals major effects on five connected areas: partisan identity, state policy, trust in institutions, elections, and democratic stability. The resurgence of measles and the COVID pandemic confirm this.
The first and most immediate effect would be sharper partisan polarization. Attitudes toward vaccination are already closely tied to partisan identity, and Republicans show more distrust of vaccines and public health agencies than Democrats. In a new epidemic, this divide would probably harden. Basic health behaviors such as getting vaccinated, wearing masks, and following school mandates would become visible political markers, and "culture war" conflicts would intensify at every level of government.
A second consequence would be policy fragmentation among the states. States are already moving in opposite directions: some are loosening vaccine requirements, while others are tightening them or forming their own public health coalitions. Another epidemic could produce a patchwork of incompatible rules on vaccination, school entry, and workplace safety. That would weaken national coordination and shift more power and visibility to governors and state legislatures.
Third, an epidemic in this climate would further erode trust in institutions. Trust in federal health agencies and in vaccines has fallen, especially among Republican-leaning voters. Leadership shakeups and politicized interventions have already damaged the CDC's authority. A new crisis amid widespread vaccine fear could speed up this erosion. It could bring more direct political attacks on health agencies and more turnover among expert leaders. People might also rely more on partisan media and influencers than on scientific bodies.
Finally, another epidemic could put serious stress on democratic norms and social stability. Past epidemics showed how disputes over mandates and individual rights can lead to protests and civil disobedience. They have also produced claims that public health measures are unconstitutional or "un-American." If fear of vaccination remains strong, another outbreak could bring sharper confrontations over emergency powers and more court challenges to mandates. It could even lead to occasional violence against health officials. Together, these pressures would further strain democratic norms and weaken public confidence that government decisions are legitimate.
In the United States, there have been 103,436,829 confirmed cases of COVID-19 with 1,232,488 confirmed deaths, the most of any country, and the 17th highest per capita worldwide. The COVID-19 pandemic ranks as the deadliest disaster in the country's history. By the end of 2022, an estimated 77.5% of Americans had had COVID-19 at least once, according to the CDC (Wikipaedia). COVID Death rates. A vaccine became available in December 2021
Duncan-Jones, R. P. (1996). The impact of the antonine plague. Journal of Roman Archaeology__, 9__, 108-136. https://doi.org/10.1017/s1047759400016524
(Denemark, Robert A. "Pandemics in Global and Historical Perspective." Globalizations 19, no. 3 (2022): 380–396. https://doi.org/10.1080/14747731.2021.1944460
Gingerich, Daniel W., and Jan P. Vogler. "Pandemics and Political Development: The Electoral Legacy of the Black Death in Germany." World Politics 73, no. 3 (2021): 393–440. https://doi.org/10.1017/S0043887121000034
Crosby, M. C. (2006). The American plague: The untold story of yellow fever, the epidemic that shaped our history. Berkley Publishing Group.
Newman, Caroline. (2020) Interview with Gingerich and Vogler https://archive.news.virginia.edu/content/qa-new-research-reveals-political-changes-wrought-black-death/
