By Samia Nakhoul, Maya Gebeily, Tom Perry and Laila BassamBEIRUT, June 11 (Reuters) - Iran is waging a calculated campaign to preserve Lebanon as its last bastion of influence on the Mediterranean, tying the country's fate to a grand bargain with Washington as it seeks to end Hezbollah's war with Israel on its own terms, not Beirut's.That effort is colliding with a historic U.S.-sponsored negotiating track between Lebanon and Israel aimed at ending decades of conflict along their frontier and redefining the balance of power in a country long caught between regional foes.

The new reality is the result of Iran’s effort to link the fate of both conflicts, and of the diverging priorities of the US president and the Israeli prime minister.

Analysis - the future of the Iran war - and the prospects for a deal to end it - could now hinge on what happens in Lebanon.