diplomatic card; bargaining chip; diplomatic leverage
Figurative term for a diplomatic asset or bargaining tool used in international negotiations. Often used in political and news contexts.
Some countries use economic aid as a diplomatic card.
That issue became an important bargaining chip at the negotiating table.
Compound of 外交 (diplomacy) and カード (card), modeled on English 'diplomatic card' or 'bargaining chip.' The exact origin is uncertain, but it likely entered Japanese through political and media usage.