Israel-Iran strikes: What are the worst-case scenarios?

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For now the fighting between Israel and Iran seems restricted to the two nations. At the United Nations and elsewhere there have been widespread calls for restraint.

But what if they fall on deaf ears? What if the fighting escalates and expands?

Here are just a few possible, worst-case scenarios.

America gets dragged in

For all the US denials, Iran clearly believes American forces endorsed and at least tacitly supported Israel's attacks.

Iran could strike US targets across the Middle East – such as special forces camps in Iraq, military bases in the Gulf, and diplomatic missions in the region. Iran's proxy forces - Hamas and Hezbollah – may be much diminished but its supportive militias in Iraq remain armed and intact.

The US feared such attacks were a possibility and withdrew some personnel. In its public messaging, the US has warned Iran firmly of the consequences of any attack on American targets.

What might happen if an American citizen were killed, say, in Tel Aviv or elsewhere?

Donald Trump might find himself forced to act. Israel's Prime Minister Benjamin Netanyahu has long been accused of wanting to drag the US into helping him defeat Iran.

Military analysts say only the US has the bombers and bunker-busting bombs that can penetrate the deepest of Iranian nuclear facilities, especially that of Fordow.

Trump promised his MAGA constituency he would not start any so-called "forever wars" in the Middle East. But equally many Republicans support both Israel's government and its view that now is the time to seek regime change in Tehran.

But if America were to become an active combatant, that would represent a huge escalation with a long, potentially devastating consequential tail.