The Observer view on US presidential election: Kamala Harris has set out her global vision. But can it work?

Most Americans pay scant attention to foreign policy and national security issues when voting for president - or so pollsters say. Yet how Kamala Harris and Donald Trump, the two possible White House successors to Joe Biden, view the world is of considerable interest to foreign audiences, not least people in Britain who hope, for example, that Keir Starmer's government will not be faced with collapsing US support for Ukraine, a Russian victory and an existential crisis within Nato. Such destabilising, dangerous outcomes appear entirely possible should Trump, a neo-isolationist ultranationalist Republican and appeaser of dictators, secure a second term….