If a camper is being towed by truck owned someone else whose insurance must cover liability for the policy or policy?

When a camper is being towed by a truck owned by someone else, the insurance that must cover liability for the trailer or camper policy is that of the truck owner, not the camper owner. This is because the truck is the primary vehicle that is towing the trailer, and therefore the liability coverage for the trailer falls under the truck owner's insurance policy.