OPINION: Risk of war returns to Europe
A century ago this weekend, my great-grandfather - a corporal in the Liverpool-recruited King's Regiment - was waiting to go "over-the-top" at the Somme.
Sent to pick up the company rum ration before the assault, he wound up drinking it and woke up after the action - or at least, that's the story he told the family after World War One was over.
Perhaps his superiors were in an unusually forgiving mood. Or perhaps, like many others, he was just looking for a way to avoid retelling his experiences. By the end of the first day, the Allies had suffered almost 60,000 casualties for precious little ground. By the time the offensive was cancelled later in the year, there were more than 800,000, over half of them fatalities.
With the two world wars increasingly passing from living memory, it's becoming easier to forget just how much they dominated the lives of almost every family on the continent.
Quietly, though, that is changing. When Nato states meet in Warsaw at the end of the week for the annual heads of government meeting of the alliance, they will be doing so amid the most serious tensions with Moscow since 1989.
Virtually no one, it must be said, thinks that either side is anything other than very keen to avoid a devastating conflict. Europe remains home to more than half the world's nuclear weapons. No one doubts that should a third major war overwhelm the continent, it would almost certainly be worse than any of those that preceded it.
And yet, a growing number believe, the risk is quietly increasing. In May, retired British General Sir Richard Shirreff - who served as Nato's deputy supreme allied commander at the time of the Russian annexation of Crimea in 2014 - wrote a book explicitly suggesting all-out war with Russia could happen as soon as next year.
On the surface, the book is a novel - but Shirreff has underlined in multiple interviews, including with this reporter, that he views it a highly plausible scenario. His former Nato boss, US Admiral James Stavridis, underlines the point in a hard-hitting introduction.
In Shirreff's book, all sides are essentially operating from a position of weakness. His unnamed Russian president - clearly modelled on Vladimir Putin - initiates hostilities with both Ukraine and the Nato member Baltic states of Estonia, Lithuania and Latvia to distract from economic woes at home, particularly a falling oil price.
Western leaders, meanwhile, overplay their limited military hand. Politicians on both sides have their eyes as much on their domestic politics as anything else. The result is a chain of errors with potentially devastating consequences.
These real-world tensions have been a long time coming. Even in the 1990s, Russian opinion - both within the military and political elite and wider country - was incensed at what felt like growing Western disdain and encroachment into what Moscow had long seen as its exclusive sphere of influence. Restoring what Russia sees as its self-respect has been at the heart of Vladimir Putin's rule.
In Crimea in particular, Moscow showed itself adept at what military thinkers increasingly call "hybrid warfare", using political manipulation and deniable forces - particularly troops without insignia - to achieve effects without resorting to conventional force. It is an area, some Western officials say, where Russia has developed a considerable lead over the West.
The lesson of the last decade, however, has also been that when it does choose to escalate to all-out military action - as it did in Georgia in 2008, Ukraine in 2014 and Syria last year - it tends to do so with much greater force and speed than Western analysts anticipated.
The problem, of course, is that no one really knows what the best way of avoiding conflict is. For Shirreff and many others, particularly in Nato's more exposed eastern states, the answer is assertive deterrence, putting enough military forces in the region to make any conventional Russian assault difficult.
Much of that is already happening, at least up to a point. The United States has dramatically ramped up its military activity in Europe since 2014, sending tanks, special forces and other personnel to frontline states as well as making high profile deployments of heavy military equipment. That includes the return of US army tanks to Europe as well as visits by state-of-the-art F-22 Raptor stealth fighters and aging Cold War-era workhorses such as B-52 heavy bombers and A-10 "tank busters".
Baltic, Nordic and Eastern European nations are ramping up defence spending - albeit several steps behind Moscow, which has poured oil revenue into its military over the last decade with the specific aim of being able to deliver overwhelming force in its very immediate neighbourhood. Already, some estimates suggest, Russia has more than enough firepower to swiftly overwhelm local and Nato forces in its immediate neighbourhood.
As in Ukraine and Georgia, the most likely flashpoints look to be regions with large ethnic Russian populations - essentially, the border districts of Lithuania, Latvia and Estonia. The governments of those countries have already stepped up development and political efforts in those regions to reduce the risks - but some analysts worry Nato's activities may end up overly militarising the situation.
As non-Nato members, neither Ukraine nor Georgia could count on Western military support when they wound up fighting Russia in 2008 and 2014. The Baltic states are a different matter - under Nato's founding charter, an attack on one is an attack on all.
During the Cold War, Nato's Supreme Allied Commander Europe [SACEUR] - always the senior US officer who also commands all US forces on the continent - had operational control of European Nato forces facing Russia. That is no longer the case, however, meaning many decisions now also require political authorisation from member states. It's the sort of messy situation that would make handling of confrontation much more difficult.
Russia has placed its nuclear arsenal at the center of its strategic approach to this kind of confrontation. According to Western experts, its recent military exercises have relied heavily on what it calls a single "de-escalatory nuclear strike".
It's a very simple - but possibly phenomenally dangerous - concept. The theory is that if Russian forces are engaged with an enemy like Nato, once they have won the conventional battle they would launch a single nuclear strike with the aim of intimidating the West into standing down and accepting the results.
In major exercises in 2013 that simulated an invasion of one or more of the Baltic states, the scenario appeared to end with a nuclear strike on Warsaw, Nato officials say. More recently - perhaps worrying that such an approach might make a Nato nuclear response inevitable - Russian exercises have tended to target a single purely military target, for example a Nato flotilla of warships.
A strike like that could kill thousands if not more - and what would happen next is almost impossible to predict. Putin might well hope such an action might fraction Nato, leaving countries hopelessly divided on how to respond. Already, opinion polls suggest German voters in particular would be reluctant to fight to defend Nato allies, while US presidential contender Donald Trump has explicitly questioned the long-term survival and purpose of the alliance.
In the era of social media and 24-hour news, however, it's equally easy to imagine a furious US electorate demanding a savage retaliation. In the post-Cold War world, after all, the United States has become used to doing what it wishes. Nor, as the UK's referendum has shown, is European politics currently particularly predictable.
Miscalculation is not inevitable. But it is arguably becoming more likely.
Just over a century ago, shortly before the Somme, future Prime Minister Winston Churchill was a battalion commander on the Western Front. He found himself in a briefing on the perceived lessons of the Battle of Loos, a bloody and unsuccessful earlier engagement that used the same tactics.
"I wanted to say 'Don't do it again'," he wrote to his wife after. "But they will."
Peter Apps is Reuters global affairs columnist, writing on international affairs, globalisation, conflict and other issues.