Iran’s commitment to causing destabilisation throughout the Arab world is the key to understanding why Donald Trump’s White House has opted to escalate tensions with Tehran.
Mr Trump has provoked considerable controversy on both sides of the Atlantic by seeking to make political capital from the certification process, whereby the White House conducts regular assessments on whether Tehran is complying fully with the terms of the nuclear deal it struck in 2015 with the US and five other world powers.
Mr Trump's decision to focus on the certification issue has provoked criticism both at home and abroad, not least because the International Atomic Energy Agency, the US-sponsored organisation charged with monitoring the nuclear deal, says that, in strictly technical terms, Iran is in compliance. This has led a number of prominent Democrats and Republicans in Washington to question Mr Trump's wisdom in focusing on certification, while Theresa May, Britain's prime minister, earlier this week phoned Mr Trump to make a personal plea not to end the nuclear deal.
But while the arguments on the certification issue are dominating the headlines, the real reason the Trump administration is spoiling for a fight with Tehran is its insistence on continuing with their efforts to spread political instability throughout the region.
When Barack Obama led the diplomatic charge to secure the agreement, which put constraints on Tehran’s attempts to develop a nuclear weapons arsenal, the clear expectation in Washington and other world capitals was that this would result in Tehran adopting a more responsible approach to the outside world.
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Instead, the opposite has been the case, with the Islamic Revolutionary Guards Corps, which remains the country's most dominant political force, using the tens of billions of dollars Iran has received as a result of the sanctions being lifted to intensify its efforts to increase Iranian influence throughout the region.
The conflict in Yemen is a case in point. The Saudi-led coalition has suffered much criticism over the humanitarian crisis now developing in that benighted country, not least because too many western media organisations seem to be conveniently overlooking the role of Iranian-backed Houthi militias in the conflict. A recent report on BBC World on the crisis, for example, went to great lengths to criticise the role of the Saudi-led coalition without once making mention of the contribution of the Iranian-backed Houthis.
The White House and other Western powers like Britain, on the other hand, have not succumbed to such a glaringly biased view of the conflict. They are well aware of Iran's malign contribution to the conflict, with the IRGC regularly sending shipments of weapons and ammunition to the Houthis for use against the Saudi-led coalition. These are thought to include some of the surface-to-surface missiles that the Houthis have used to attack targets within Saudi Arabia itself, including at least one missile attack that was directed against the holy city of Mecca.
The dispute between Qatar and the quartet of Arab states over Doha's support for terrorism is another example of how Iran seizes on any opportunity to meddle in the affairs of the Arab world. No sooner had the Arab coalition decided to take measures against Qatar to persuade it to end its support for Islamist militants than Tehran had offered its support to Qatar.
Iraq, Syria, Lebanon and Bahrain are among the many Arab countries that have been on the receiving end of unwarranted and unwelcome interference on the part of Iran in their affairs.
And if that was not enough, Iran has also continued investing in its ballistic missile programme which many intelligence experts believe is intimately connected with the nuclear programme, and represents a clear violation of the spirit of the nuclear deal.
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If Iran was really serious about giving up its aspirations to develop nuclear weapons, intelligence officials ask, then why is it still investing heavily in its missile programme?
It is no secret that, in the past, Iran has worked closely with North Korea on the development of sophisticated missile technology, and the concern now in Washington security circles is that the recent improvements in North Korea's missile systems, which are now believed to have the range to target America and Europe, could soon be passed to Tehran.
These, then, are the real reasons why the Trump administration appears so determined to initiate a new era of confrontation with Iran, and why there is much more to the row over decertification than meets the eye.
Mr Trump made it abundantly clear where his regional priorities lie in the Arab world when he visited Saudi Arabia this year, and pledged a new era of close cooperation with Riyadh. And by doing so, it follows that the president is going to take a dim view of a country like Iran whose entire raison d'etre seems to be to undermine Saudi interests and influence at every turn.
And if this means that, in order to hold Iran to account for its actions, Mr Trump is prepared to ditch the nuclear deal, then so be it. For when it comes to dealing with Iran’s nuclear ambitions, Mr Trump would not be the first person to conclude that no deal is better than a bad deal.
Con Coughlin is the Telegraph’s Defence and Foreign Affairs Editor and author of Khomeini’s Ghost: The Iranian Revolution and the Rise of Militant Islam