Tensions are running high in the Middle East in the waning days of the Trump administration.
Over the weekend, Iran's foreign minister, Mohammad Javad Zarif, claimed Israeli agents were planning to attack US forces in Iraq to provide US President Donald Trump with a pretext for striking Iran.
Just ahead of the one-year anniversary of the US assassination of Iran's charismatic General Qassem Soleimani, Iran has warned it would respond forcefully to any provocations.
"Today, we have no problem, concern or apprehension toward encountering any powers. We will give our final words to our enemies on the battlefield," said General Hossein Salami, the top commander of Iran's paramilitary Revolutionary Guard.
Israeli military leaders are likewise preparing for potential Iranian retaliation over the November assassination of senior Iranian nuclear scientist Mohsen Fakhrizadeh — an act Tehran blames on the Jewish state.
Both the US and Israel have reportedly deployed submarines to the Persian Gulf in recent days, while the US has flown nuclear-capable B-52 bombers to the region in a show of force.
And in another worrying sign, the acting US defence secretary, Christopher Miller, announced over the weekend the US would not withdraw the aircraft carrier USS Nimitz and its strike group from the Middle East — a swift reversal from the Pentagon's earlier decision to send the ship home.
Israel's priorities under a new US administration
Israeli Prime Minister Benjamin Netanyahu would like nothing more than action by Iran that would draw in US forces before Trump leaves office this month and President-elect Joe Biden takes over. It would not only give him the opportunity to become a tough wartime leader, but also help to distract the media from his corruption charges.
Any American military response against Iran would also make it much more difficult for Biden to establish a working relationship with Iran and potentially resurrect the 2015 Iran nuclear deal.
It's likely in any case the Biden administration will have less interest in getting much involved in the Middle East — this is not high on the list of priorities for the incoming administration. However, a restoration of the Iranian nuclear agreement in return for the lifting of US sanctions would be welcomed by Washington's European allies.
This suggests Israel could be left to run its own agenda in the Middle East during the Biden administration.
Israel sees Iran as its major ongoing security threat because of its support for Hezbollah in Lebanon and Palestinian militants in Gaza.
One of Israel's key strategic policies is also to prevent Iran from ever becoming a nuclear weapon state. Israel is the only nuclear weapon power in the Middle East and is determined to keep it that way.
While Iran claims its nuclear programme is only intended for peaceful purposes, Tehran probably believes realistically (like North Korea) that its national security can only be safeguarded by possession of a nuclear weapon.
In recent days, Tehran announced it would begin enriching uranium to 20 per cent as quickly as possible, exceeding the limits agreed to in the 2015 nuclear deal.
This is a significant step and could prompt an Israeli strike on Iran's underground Fordo nuclear facility. Jerusalem contemplated doing so nearly a decade ago when Iran previously began enriching uranium to 20 per cent.
How the Iran nuclear deal fell apart
Iran's nuclear programme began in the 1950s, ironically with US assistance as part of the "Atoms for Peace" programme. Western cooperation continued until the 1979 Iranian Revolution toppled the pro-Western shah of Iran. International nuclear cooperation with Iran was then suspended, but the Iranian programme resumed in the 1980s.
After years of negotiations, the Joint Comprehensive Plan of Action (JCPOA) was signed in 2015 by Iran and the five permanent members of the UN Security Council and Germany (known as the P5+1), together with the European Union.
The JCPOA tightly restricted Iran's nuclear activities in return for the lifting of sanctions. However, this breakthrough soon fell apart with Trump's election.
In April 2018, Netanyahu revealed Iranian nuclear programme documents obtained by Mossad, claiming Iran had been maintaining a covert weapons programme. The following month, Trump announced the US withdrawal from the JCPOA and a re-imposition of American sanctions.
Iran initially said it would continue to abide by the nuclear deal, but after the Soleimani assassination last January, Tehran abandoned its commitments, including any restrictions on uranium enrichment.
Israel's history of preventive strikes
Israel, meanwhile, has long sought to disrupt its adversaries' nuclear programmes through its "preventative strike" policy, also known as the "Begin Doctrine".
In 1981, Israeli aircraft struck and destroyed Iraq's atomic reactor at Osirak, believing it was being constructed for nuclear weapons purposes. And in 2007, Israeli aircraft struck the al-Kibar nuclear facility in Syria for the same reason.
Starting in 2007, Mossad also apparently conducted an assassination programme to impede Iranian nuclear research. Between January 2010 and January 2012, Mossad is believed to have organised the assassinations of four nuclear scientists in Iran. Another scientist was wounded in an attempted killing.
Israel has neither confirmed nor denied its involvement in the killings.
Iran is suspected to have responded to the assassinations with an unsuccessful bomb attack against Israeli diplomats in Bangkok in February 2012. The three Iranians convicted for that attack were the ones recently exchanged for the release of Australian academic Kylie Moore-Gilbert from an Iranian prison.
The Mossad assassination programme was reportedly suspended under pressure from the Obama administration to facilitate the Iran nuclear deal. But there seems little doubt the assassination of Fakhrizadeh was organised by Mossad as part of its ongoing efforts to undermine the Iranian nuclear programme.
Fakhrizadeh is believed to have been the driving force behind covert elements of Iran's nuclear programme for many decades.
The timing of Fakhrizadeh's murder put the Iranian regime under domestic pressure to retaliate. If it did, however, it risked a military strike by the truculent outgoing Trump administration.
It's fortunate Moore-Gilbert was whisked out of Iran just before the killing, as there's little likelihood Iran would have released a prisoner accused of spying for Israel (even if such charges were baseless) after such a blatant assassination had taken place in Iran.
What's likely to happen next?
Where does all this leave us now? Much will depend on Iran's response to what it sees (with some justification) as Israeli and US provocation.
The best outcome would be for no obvious Iranian retaliation or military action despite strong domestic pressure for the leadership to act forcefully. This would leave the door open for Biden to resume the nuclear deal, with US sanctions lifted under strict safeguards to ensure Iran is not able to maintain a covert weapons programme.