US midterms: Why are there so many guns in campaign ads?

US political campaigns have spent more than $6bn (£5.2bn) on adverts this year, a new record.

Republicans and Democrats have focused on very different issues and contrasting visions of America - but both have played on voters' fears.

Katty Kay decodes the two parties' election messages.

Produced by the BBC's Jason Armesto and Grace Conley.