The Guardian | Simon Tisdall: Iran has military, covert and diplomatic options. And this new phase of the confrontation could quickly get out of hand�

On the outskirts of Tehran, vast cemeteries serve as a grim reminder of the high price Iran paid during its 1980-88 war with Iraq. Hundreds of thousands of young Iranians fought and died in a horrific struggle against Saddam Hussein�s invasion forces, which were armed by the US. Among those Iranian soldiers who survived was Qassem Suleimani.

The war, by all accounts, was a formative experience for the man who would later rise to a dominant position in Iran�s military, security and intelligence establishment. Suleimani�s loyalty to Iran�s revolutionary regime, which seized power in 1979, was firmly established. His belief that an implacable America was his country�s foremost foe was written in blood.

Suleimani became the chief architect of the expansion of Iran�s regional influence, which began in earnest following the American toppling of Saddam in 2003. It enabled Tehran to establish the kind of dominance in Iraq that previously eluded it. Iran�s reach gradually extended to Syria, Gaza, Lebanon and Yemen, always in opposition to the US and its allies.

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