Nato: US military presence in Europe

A US carrier strike group - a major fleet of warships - is a potent symbol of American military power and a signal that it's willing to defend allies and deter enemies.

So the presence of such a force in the North Sea over the past few weeks is meant to reassure European allies, despite the political uncertainties back home.

American military power has helped protect Europe for the past 75 years - but the US presidential election raises the question: for how much longer?

Military commanders do their best to avoid politics.

But among a group of journalists ...