Last week was not the first time in American history that a crazed assassin has tried to change the trajectory of the government by killing political enemies. In 1865, when it was clear that the confederacy was about to collapse, prominent southerner John Wilkes Booth and his accomplices set out to behead their Republican opponents by killing President Abraham Lincoln, his vice-president, Andrew Johnson, and the secretary of state, William Henry Seward.

The grand tragedy that martyred President Lincoln seems to dwarf the farce of a MAGA (make America great again) -inspired former exotic dancer, Cesar Sayoc, mailing homemade pipe bombs to Democratic leaders. But the same misguided patriotism inspired both.

In both eras, the course that led to assassination attempts started when a small group of wealthy men recognised that their economic interests ran counter to those of most voters. Setting out to shore up their waning influence, by limiting access to information, dominating government and warning supporters that political enemies were urging minorities to harm them, they built a fervent following. Those followers came to believe America was a white man’s land and saw those challenging their leaders as dangerous radicals.

When a president demonises opponents as an un-American mob trying to destroy the country, it is not a lunatic who tries to harm them, it is a patriot.

In 1861, they backed their leaders’ new nation, conceived in the belief that the commitment of America’s founders to equality was an error and they, alone, had figured out how to run the nation. Their followers took up arms not to destroy American democracy but to save it.

The parallels with today are too obvious. When a president, as Trump does, demonises opponents as an un-American mob trying to destroy the country, it is not a lunatic who tries to harm them, it is a patriot.

In the mid 19th century, it had taken a generation of political rhetoric to induce southern soldiers to fight for the interests of a small ruling class in the name of democracy. In the 1830s, the rapid growth of the north threatened to overwhelm the power of southern slave owners in the federal government. Determined to protect the slave system that made them rich, they challenged any government action that might weaken slavery.

By contrast, during the war, Lincoln and the Republicans in Congress used the government to promote equal opportunity, but the very popularity of that government led Democratic opponents to howl that Lincoln was a tyrant, trampling property rights and destroying liberty. When the actor Booth dispatched the bullet that killed the president in 1865, he shouted: “Sic semper tyrannis” (thus always to tyrants) – the state motto of Virginia and Brutus’s explanation for his murder of Julius Caesar in Booth’s favourite Shakespeare play.

It is a different Cesar on the stage in America today, but the process by which he got there is the same as the one that seduced Booth. Since the 1980s, Republicans have argued that policies embraced by a majority of Americans to promote equality of opportunity actually infringe liberty by hampering businessmen’s actions or taking their money through taxes. To advance this idea, the Reagan administration in 1987 abandoned the “fairness doctrine” that required media to present factual information and balance opposing viewpoints, giving free range to rightwing talk radio shock jocks such as Rush Limbaugh who pushed the idea that business regulation and social welfare policies destroy American liberty.

When voters, nonetheless, elected Bill Clinton in 1992, Republicans started the Fox News Channel, an entertainment network that deliberately pretended to be news, with media “personalities” constantly warning that Democrats were anti-American socialists. In their formulation, the Democrats were buying the votes of minorities and “feminazis” by offering benefits such as housing, education, jobs and free phones, all paid for with white tax dollars. Lazy Democratic voters were “takers” who threatened the individuals who made America great.

By the 1990s, Republicans held on to power by manipulating the system. They claimed Democrats won elections through “voter fraud” and that they were protecting democracy. They deliberately kept Democrats from the polls. Voter suppression in Florida in 2000 helped put Republican George W Bush into office despite losing the popular vote and the targeting of state legislative elections in 2010 enabled Republicans to gerrymander states out of Democrat reach.

Meanwhile, from the 1980s, Republicans insured themselves against Democratic legal challenges by packing the courts. Always, they argued that their machinations were simply protection against Democratic plotting with undeserving minorities to destroy America. By 2018, the Republicans’ president had demonised minorities as criminals and rapists and had embraced the idea that America was a white man’s land.

They retained power by skewing media and convincing white followers that dangerous minorities threatened their existence

Since 1980, Republicans have monopolised resources for a few wealthy Americans and have retained power by skewing the media, manipulating the system and convincing white followers that dangerous minorities threatened their very existence.

In the 19th century, when northerners tried to challenge the plantation owners’ dominance by urging poor, white southerners to turn against a slave system that consolidated land and capital among a few men, the large planters responded by censoring the press. They insisted discussion of slavery was designed to encourage slaves to rise up and murder southerners in their beds and they silenced debate over their peculiar institution.

By the late 1850s, frantic planters demonised anyone who questioned their control of government. So dangerous were the Republicans, slave owners told their voters, that, despite Lincoln’s assurances that he had no intention of interfering with slavery, his election would be grounds to destroy the Union. Southern leaders did not wait to see what president-elect Lincoln would do. Even before his inauguration they had organised their own nation. They refused all popular calls for government involvement in the economy, insisting that the founders’ government was designed to do nothing but protect property. Active government was unconstitutional, they argued, it impinged on the liberty of wealthy men.

As in the civil war era, the political culture of today’s America suggests to unhinged partisans that the patriotic way to protect American democracy is by destroying it.