Mountains on one side, a lake on the other, the genteel spa town of Évian-les-Bains near France’s border with Switzerland was chosen to host the leaders of seven of the world’s largest economies because it is strategically suitable to secure.As United States president Donald Trump arrived at the G7 by helicopter on Monday, it was the moment of highest alert in a vast French security operation many months in the making that has affected the entire area for 50km around.Quiet Alpine ski villages an hour or more from the epicentre, usually all but shuttered for the off season, were bristling with military police, their chalets and hotels opened up to house the 15,000 law enforcement officers brought in to secure the summit.Convoys of blue police vans moved along the narrow mountain roads while swarms of police monitored the minor crossings with Switzerland, halting passing cars for inspection.The ski resort of Avoriaz is housing 2,500 police officers including multiple squadrons of riot police. A convention centre on the outskirts of the medieval village of La Roche-sur-Foron has been made into a forward operation base for the national military police, overseeing the movements of their 6,100 officers and 1,400 vehicles deployed to police the G7.Meanwhile, 30 police boats kept guard on the waters of Lake Geneva.At the centre of it all, Évian – the source of the well-known brand of bottled water – is dwarfed by the operation, with a population of about 9,000, far outnumbered by the security forces deployed to police it.Police boats patrol Leman lake in Évian, France, on Sunday, before this week's G7 summit. Photograph: Yoan Valat/EPA Évian has been divided into red and blue “zones” since Thursday. The “red zone” encompasses the Royal Évian Resort and its surroundings, where the leaders of the US, United Kingdom, Canada, France, Germany, Italy and Japan have gathered, to be joined by the leaders of Egypt, the United Arab Emirates, India, Saudi Arabia, Australia, Brazil, Kenya and South Korea. It is entirely closed off by a security cordon.A broader “blue zone” encompasses all of Évian and some of its adjoining suburbs, and is accessible only with a permit that residents, employees and anyone with a need to be in the town had to apply for weeks in advance.The security cordon came into force at midnight on Wednesday, days before the summit began, suspending the train line into the town and closing roads all around it with police checkpoints. It is to remain in force for a week.The greatest security concern is some kind of attack on the summit – French officials refer to the delicate international context – but it is also to guard against protests. Thousands of diffuse protest groups brought together under a “No G7” banner marched in Geneva in advance of the summit, and three people were detained after a car was set on fire and the windows of a bank smashed.There is some resentment in Switzerland about the decision to hold the summit so close to its border, requiring the use of Geneva airport and wide-ranging security measures on the Swiss side too.Estimates of the cost of the security operation have not been made available. But it underlines that for French president Emmanuel Macron, who is hosting his final G7 summit, a successful event will be one in which nothing goes wrong.Police officers in riot gear during a 'no G7' rally in Geneva on Sunday in advance of this week's summit of world leaders. Photograph: Fabrice Coffrini/AFP via Getty Images There is no expectation the event will produce a great agreement or decision among leaders. It is a “defensive” summit, in more ways than one. The entire effort of France for over a year has been to ensure that Trump would not snub the summit by deciding not to attend, preserving the appearance of co-operation even if in reality the US is no longer pursuing the same interests as the others in the group.Enormous lengths were taken to ensure Trump does not pull out: the date of the event was shifted so that it didn’t clash with his 80th birthday celebrations; any offensive topic such as climate change or development aid is off the agenda.Once, a G7 meeting of leaders would be expected to address big topical crises such as the uncontrolled spread of the Ebola virus in the Democratic Republic of the Congo or the war in Sudan. The idea would be to agree a common approach and then jointly exert pressure for a solution.There will be no attempt to agree a joint declaration at the event but rather several inoffensive thematic “texts”: on critical minerals, on child protection online, on cancer research.Macron’s office already touts the summit as a success. “The international political reality is what it is,” an Élysée source said. “This G7 is focused on convergence.”However, the extreme modesty of the hoped-for outcomes – primarily, that Trump would not walk out or sabotage the summit in some unexpected way – reflects a broader collapse in the ability of countries to co-operate internationally to achieve common aims.