International summits come and go, amid flurries of staged photos and unread communiqués. But the G7 meeting in Cornwall later this week could be a rare such event that actually matters — for the individual countries involved, for the western alliance and for the wider world.

For Boris Johnson, who is hosting the meeting, it is a chance to counteract any lingering impression that he is a cynical lightweight, and to demonstrate that he can steer a major international meeting. The UK prime minister also needs to show that “Global Britain” is more than a slogan.

For Joe Biden, on his first trip overseas as US president, it is an opportunity to demonstrate that America is back. Biden has made it clear that he intends to rally the world’s democracies in pushing back against Russia and China.