Imagine a 17-year-old black teenager in the US taking up an assault rifle and travelling to a neighbouring state. He joins vigilantes claiming to protect property during contentious street protests. The black teenager shoots two protesters dead and wounds a third, but a jury finds him not guilty of any offence. That, more or less, is the story of Kyle Rittenhouse, now aged 18, but with one big difference. Mr Rittenhouse is white. His victims were supporters of Black Lives Matter. And the local police, in an area where in 2020 an officer shot dead a black man, Jacob Blake, in the back, were very accommodating towards Mr Rittenhouse and those armed white vigilantes. Would a black teenager have been acquitted of the killings? President Joe Biden said it is necessary to “acknowledge that the jury has spoken” in acquitting Mr Rittenhouse, but he also noted something very disturbing about the verdict, which re-opens America’s many unhealed wounds. Slavery, the Civil War, the civil rights protests of the 1960s, the Rodney King beating case of the 1990s and the Black Lives Matter protests of the 2020s are not past history. They are part of today’s "dis-United States", and what we now call “Culture Wars,” those differences of opinion in which the gulf between Americans is less about resolving policy disputes than about entrenched ideology, and contradictory values, practices and beliefs. American politics is often a blood sport. But even in the contentious Nixon or Reagan eras of the 1970s and 80s, Democrats and Republicans often co-operated. Constitutional democracies can only function if political leaders go beyond the written words of the constitution and observe at least some norms of civil behaviour. Republican President Ronald Reagan had no more wily a political foe than Democratic Speaker of the House of Representatives Tip O’Neill. O’Neill called Reagan a “cheerleader for selfishness”. But, as O’Neill’s successor as Speaker, Tom Foley, once proudly told me, O’Neill and Reagan were both (like Foley himself) fundamentally good-natured Irish Americans, patriots for whom political hostilities ended at sundown, at which time they would often share a drink. Reagan once famously said, “Tip, you and I are political enemies only until six o’clock. It’s four o’clock now. Can we pretend it is six o’clock?” Both men recognised the art of compromise is important in the US system of governance. But by the 1990s something changed. One example is the Republican Whip (and later Speaker of the House of Representatives) Newt Gingrich, who personified a new kind of hyper-partisan politics. Mr Gingrich and his colleagues in 1990 produced a pamphlet for Republican candidates titled <i>Language: A Key Mechanism of Control</i>. He selected “optimistic governing words” to help Republicans “give extra power to your message”. These positive words included: courage, common sense, dream, fair, family, freedom, hard work, liberty, tough, vision and many others. There were negative words, too, and Republicans should “apply these to your opponent”. These include: bureaucracy, cheat, collapse, corruption, crisis, decay, hypocrisy and incompetent. The key is that these words signify two tribes, Us and Them. They do not signify policies or ideas. There is no middle ground here, only abuse and emphatic difference. Mr Gingrich, a highly intelligent and affable man, employed his particular genius to define the Culture Wars through emotive wedge issues – guns, abortion, race, gender, welfare and crime – "hot-button" issues which stir up voters much more than questions about economic policy. Mr Gingrich did not invent these divisions. But he did weaponise them. In Congress, Republican Culture Warriors used what some call “weapons of mass obstruction” to stymie the political decisions taken by Democratic presidents Bill Clinton and Barack Obama. These weapons ranged from filibusters in the US Senate to enforced government shut downs in 1995 and 1996 against Clinton’s budget plans, and another shutdown in 2013 against Obama’s healthcare proposals. Democrats adopted the same strategy in the 35-day shutdown of 2018 and 2019 during the Trump presidency, amid rows about immigration. What does this have to do with Mr Rittenhouse? Everything. As US National Public Radio’s Dan Gonyea put it, the Gingrich shutdown of 1995 is now commonly recognised “as a landmark in US political history, birthing a new era of American gridlock that arguably led to the sharp partisanship that has gripped the nation”. Hyper-partisanship means that rather than “binding up the nation’s wounds”, as Abraham Lincoln wanted to do in 1865 at the end of the Civil War, America’s 21st-century cultural conflicts are uncivil wars with no obvious resolution. Mr Rittenhouse's supporters glorify his actions. FOX News treats him as both victim and hero. Others believe Mr Rittenhouse acted criminally and was treated very differently to any black teenager might have been. Mr Gingrich’s vocabulary of Liberty or Corruption, Us and Them, has no middle ground. Neither, sadly, does American politics in 2021. And behind all of this there is another obvious question: Whatever the jury’s verdict, why does the world’s most modern democracy think it is somehow acceptable, even normal, for a 17-year-old to walk the streets far from home carrying a loaded, military-grade assault rifle?