Iran is one of the world's most significant nations in terms of history, culture and intellectual capacity, and is matched in the Middle East perhaps only by Israel.
It is a small wonder, then, that when Iran's hard-line and irascible president talks of building military capability and destroying Israel, Tel Aviv feels its survival is menaced and that Tehran's regime is its nemesis.
For all of its 61 years in existence, Israel has considered itself in a permanent war of survival. It has developed a national system which places great emphasis on its military and intelligence capabilities.
Starting from scratch, Israel has developed technologies which are truly world-leading, especially in the delivery of shock and awe on any potential enemy.
For the early part of its statehood, Israel had shared the support of the United States, as its protector and military hardware supplier, with the Shah's Iran.
When a belligerent Saddam Hussein took power in Iraq, both the Shah and Israel were uneasy and often co-operated in exploiting technology, both US and home-grown in Israel.
There is documented evidence that Israel supplied Iran with communications equipment and the supporting paraphernalia needed to allow both countries (and probably the US Central Intelligence Agency) to eavesdrop on Iraq.
The great divide
The Iranian Revolution changed all that and since 1980, Israel and Iran have grown apart. So far apart, in fact, that there is a real risk of armed conflict between the two states.
What makes the world sit up and take note is that Israel is a nuclear power with delivery systems which can reach Iran – and Iran is, according to US experts, just two years away from creating a nuclear strike capability of its own.
US experts believe Iran will be able to produce nuclear weapons material in the next few months.
For Jordan, Iraq and Saudi Arabia – and even the Gulf states - this is particularly worrying as any nuclear-tipped missiles would fly overhead no matter who launches them.
In addition, Israel has a sophisticated - and tested - anti-missile system called Arrow, which could knock out a potential Iranian first strike. The problem for Israel's neighbours is not the technology but where the debris might fall if the Arrow were ever to be used.
Israel has watched with growing horror as the rhetoric from Mahmoud Ahmadinejad, the Iranian president, stokes tensions and as Tehran appears to be determined to create a full nuclear weapon capability.
Israel has taken steps to improve its nation's defences and its long-range strike capability. There is no doubt that the Israeli military could mount a successful air strike against targets in Iran and certainly that the Jericho series of ballistic missiles could hit targets with great accuracy.
But it is also clear that any such first strike would provoke clear and rapid hostile reactions around the world, especially from moderate Arab nations with whom Israel seeks accord and co-operation against Iran, as well as by the European Union and others opposed to first strike operations – in favour of a self-defence option.
The Middle East peace process would be indirectly destroyed and Iran's proxies in Lebanon and Gaza would probably enter the fray against Israel.
Israeli interests worldwide could also be threatened.
Iran is not yet in a position to launch a first strike against Israel. This is perhaps a key concern because Israel has a reputation for not allowing a first strike capability to develop.
It has a record of destroying the Egyptian ballistic missile industry under Gamal Abdel Nasser, the late Egyptian president; destroying French-built Iraqi nuclear reactors outside Baghdad at Osirak in 1981, and interdicting the supply of arms moving through Sudan as recently as January this year.
Nevertheless, Iran has had a series of short-range ballistic missiles for three decades, having developed them for the 'War of the Cities' during the war with Iraq. Much of the technology was originally bought from Pakistan and later North Korea.
There is Russian and Chinese technology extant as well – even technology bought commercially in electronics supermarkets in Japan as a report in Jane's Defence Weekly revealed 15 years ago.
But creating a weapon in sufficient numbers and capability to destroy key targets in Israel is a different matter.
Even if Iran had a nuclear device now, it would take some time to 'weaponise' it to create a first strike capability. North Korea is struggling with same problems which leads many to believe there is a union of need between the two otherwise unlikely bedfellows.
Black market technologies
Iran's defence industries have created good technologies of their own since the US-inspired arms embargo which followed the cessation of hostilities with Iraq in 1988. Battlefield weapon systems were developed from black market Russian missiles and by some clever adaptations of US technology.
For example, Iran's military took medium-range air-to-air missiles (originally exported to Iran in the time of the Shah for the F-14 Tomcat and F-4 Phantom fleets) and reconfigured the guidance systems from air-to-air to air-to-ground.
Israel has also seen Iran, under Ahmadinejad, support both Hezbollah and Hamas. Recent military operations in South Lebanon in 2006 and against Hamas in Gaza in 2009 have witnessed a haul of Iranian-supplied systems.
Israel has put extreme diplomatic pressure on Russia about the extent of weapons sales to Iran. The unlikely alliance between Iran and Syria has also contributed to Israel's unease and feeling that it is - like in the early 1960s - surrounded by potential aggressors.
Washington's anti-Iran stance under George Bush, the former US president, led to speculation that the US would provide the technology for Israel to launch a conventional bombing raid – or rather series of raids – against Iranian nuclear facilities in known locations near Shiraz and Isfahan.
What to bomb?
The problem for Israel in mounting such operations would not be the technology of reaching the target areas, nor destroying those seen, or even the opposition of neighbours, but actually detecting the right facilities.
Iran, using North Korean advisers, has managed to bury and hide its main facilities. This makes a first strike difficult in military terms while the risk of collateral damage makes it impossible in political terms.
Israel has been trying a charm offensive with some moderate Arab states. It has highlighted that the physical and political fallout stemming from Ahmadinejad's more aggressive posture would be damaging for all.
Israel's case has not been helped by Operation Cast Lead, the name it gave its offensive against Hamas in Gaza last January.
Ahmadinejad's inauguration for a second term after the disputed elections is another factor. Traditionally, leaders under pressure in hard-line states have used military adventures to divert public opinion.
One only has to remember the actions of the Argentine Junta in 1982 when it invaded the Falkland Islands or actions in Northeast Africa over several decades.
Military and intelligence organisations look at a nation's potential threat by examining key attributes.
These are 'military capability' – could a nation actually carry out a military strike; "political will" – does a nation actually want to expend that much treasure and 'blood'; "an understanding of the consequence" – does the nation's leadership understand where the ripple caused by its casting of a stone into the pool of peace would stop?
Hard-line versus unpredictable
Taking each nation in turn – Israel has the military capability of a nuclear or non-nuclear strike against Iran and hence the war experience of 1967, 1973 and 1982 to fall back upon.
The current government in Tel Aviv is hard-line enough to both take the action and to ride out the political storm.
But it is also pragmatic and - despite its inability to understand the West's clear opposition to its housing policies in Jerusalem and the West Bank - guarded in its use of military force on a regional scale.
US posture is also a determining factor in any decision to strike. The fate of three US tourists apparently being held by Iran could further bolster the position of US hawks on Iran in the Obama administration.
Iran, on the other hand, is completely unpredictable, especially given the competing power structures within the country.
It has a recent history of meddling in the affairs of its neighbours, like the fledgling Iraq, and launched a million men and young boys in human waves against Saddam Hussein's armies dug in along the border in the 1980s.
The religious leaders of the time seemed quite happy to allow this wholesale slaughter without any sign of remorse. So the question remains, would Iran's leadership launch a nuclear strike against Israel?
Today, it cannot because the technology is not there. Will it at some time in the future if Iran were to ever develop such means?
The rest of the world can only hope that sense prevails in Tehran and the internal situation is resolved in a way that does not 'force' Ahmadinejad to take the 'nuclear option' – not literally, but by creating the conditions for war in order to reinforce his own embattled and increasingly fragile position as leader.