When the leaders of Japan, South Korea and the United States stood together at the rustic Camp David presidential retreat to announce “a new era” of trilateral cooperation, they were quick to offer reassurances that their historic pledge will have staying power.

Whether that will be the case remains up for debate, though a confluence of factors — including rising concerns over China’s moves near Taiwan and in the East and South China Seas, as well as alarm at the pace of North Korea’s nuclear and missile breakthroughs — could help pave the way for a durable three-way relationship.

Experts say the summit was another significant step toward deepening and expanding trilateral cooperation across a broad swath of areas as diverse as diplomacy, technology education and security.