I crisscrossed America to talk to people whose views I disagreed with. I now have one certainty

I've spoken to white nationalists in Tennessee and Black activists in Texas - and learned about what it takes to connect across difference

The residential community was lodged near a national forest on the outskirts of Scottsdale, Arizona. Forbidding gates and sentry posts restricted access to the exclusive development and its elegant homes. But security here went much further.

Each cul-de-sac in the colony had its own individual railway gate, and many of the homeowners had installed gates across their own driveways as well. Anyone coming in or out of those houses would have to clear three checkpoints that set them apart from the wider world beyond.