This article has also been published inThe Conversation in a subsequently updated version.

Signed by the P5 + Germany and mediated by the EU’s foreign policy chief, Baroness Catherine Ashton, the deal achieved with Iran on the latter’s nuclear programme has important implications for regional and international security dynamics that go well beyond nuclear weapons.

The deal means that Israel, for the foreseeable future, will remain the Middle East’s only nuclear-armed power. With Iran having compromised on key Western demands regarding enrichment and enrichment capabilities and subjecting its nuclear facilities to the possibility of daily inspections, Saudi justifications for its own nuclear weapons programme – and to a lesser extent Egyptian – are less convincing for the time being. In that sense, the balance of power in the Middle East remains the same for now.

In other important ways, however, that balance of power has shifted. Iran is no longer the almost universally agreed outcast. It has made a deal with key Western powers, above all the United States whose hostility to the regime of the Ayatollahs had been taken for granted through decades punctuated with failed diplomatic efforts as much as its alliance with Israel and Saudi Arabia.

That the deal was made, against the objections of these two key Western allies, is significant in itself. It indicates the continuation of a longer-term trend of increasing disaffection and dissatisfaction Israel over the slow progress of the Israeli-Palestinian peace process and with Saudi Arabia over its poor human rights record and funding of Islamist groups not known for their subscription to Western ideas and values.

The deal was not made because of this, but increasingly fractious relations with both countries put less of an obstacle in its way than might have been the case a few years earlier.

Israel and Saudi Arabia both feel similarly threatened by Western rapprochement with Iran, as they do by Iran itself. Even though Tel Aviv remains openly opposed to the deal, while Saudi Arabia gave it a cautious welcome, at a regional level both countries now have, more than ever, some common interests – despite continuing long-standing disagreements. While an official rapprochement between Israel and Saudi Arabia is unthinkable at the moment, both states will do whatever they think is necessary to avoid any further rebalancing of power across the Middle East.

For the time being, however, their options to do so are limited. Iran has yet more cards to play. Apart from co-operation on the present six-month deal, it is likely that the country will continue to engage in further constructive negotiations over its long-term nuclear programme. If the currently positive momentum is retained, a more permanent deal, though still not easy, is more likely than not, including further easing of sanctions and consequently growing Iranian economic power and political influence.

At the same time, Iran will remain a crucial player in the Syrian crisis. If a real peace process gets underway, collaboration from Tehran will be indispensable and may be, combined with Russian support, the only way to get the regime to think beyond Assad.

While Saudi Arabia, through its influence on significant sections of the rebel movement, could still thwart a negotiated agreement, this is clearly not in Israel’s interests. A negotiated exit for Assad, a transitional power-sharing government and a prevention of a complete collapse into anarchy in Syria are, in fact, objectives where Tel Aviv might find itself much more closely aligned with Washington and Tehran than with Riyadh.

The Syria crisis, including the chemical weapons deal there, and the Iran nuclear deal, however, also indicate the continuing importance of Russia in the region and thus the need for Western co-operation with Russia. In fact, it highlights the importance of global diplomacy and the necessity for all the major powers to seek workable compromises where and when these are possible.

This is particularly important at a time when relations between Russia and the EU are heading towards a new low over the EU’s Eastern Partnership. The fact that a deal was possible on Iran and that we might yet see a meaningful peace conference on Syria indicates a degree of issue-specific, interest-based flexibility that has been absent from great-power diplomacy for some time.

Russia’s quasi-reaffirmation as a significant power has gone hand-in-hand with a recognition, albeit perhaps not as obvious, of the EU as an increasingly important player on the international security scene. The Iran nuclear deal will be a defining feature of Baroness Ashton’s legacy. It may not signal a breakthrough for the EU into the league of international security heavy-weights, but after the disappointments during the Arab Spring it marks an increase in the relevance of the EU in the region and vis-a-vis other global players there.

The key challenge now is for those involved in the Iran nuclear deal to turn it into something that is both sustainable in the long term and not perceived as threatening in the region. Israeli and Saudi fears of Iranian intentions are based not on paranoia but on an Iranian track record of rhetoric and action that does not instil natural confidence into the regime. Yet without giving Iran a chance to prove that these perceptions – turned predictions – are unfounded, no good is likely to come from the deal that has been achieved now.

Putting some faith into the durability of rapprochement need not undermine either Israel’s or Saudi Arabia’s security. On the contrary, it could be the beginning of a rebalancing of power in the Middle East from which everyone could benefit.