Possible Clues:

• Diplomat's stock-in-trade
• Goes around Taoiseach to contradict diplomacy
• Sensitivity in dealing with others
• Negotiating asset
• Touch one for a hundred on this with diplomacy
• It's needed by diplomat, actually
• Statesman's asset
• What boors lack
• '___ teaches you when to be silent': Disraeli
• In this roughly sewn, by the sound of it, politely