The surprise announcement that the Gulf Cooperation Council wants to expand its membership to Jordan and faraway Morocco raises a key question: what exactly is the GCC? Is it a loose political coordination group, a fledgling economic bloc or a rising security alliance?
Of course it can try to be all three of these. The European Union, which was founded as an economic bloc, extended membership to the east for security reasons - to rescue the Poles and others from Russian domination. But an organisation needs one over-arching goal if it is going to succeed in bringing together countries that treasure their independence.
The EU is seen as a great success. But still, half a century after its founding, it faces ever deeper problems in integrating its members economically. And it is easy to forget that its attempts at a common foreign and security policy have stumbled at every new crisis.
To understand the GCC, it is easiest to look at its roots. It was founded in 1981 during the Iran-Iraq war. In the following years, differences between the member states and weak leadership have held it back. It missed a 2010 deadline for a planned currency union.
The drift ended with the Arab Spring. American acquiescence in the fall of US-supported regimes in Tunisia and Egypt proved to the Gulf countries that reliance on outside help was no longer a policy. In a world where the US is overstretched and Iran is perceived as a threat, there was clearly a need for the GCC to start taking action as a bloc.
The GCC put forward a plan for a peaceful transition of power for the embattled Yemeni president Ali Abdullah Saleh, and intervened with force to support the monarchy in Bahrain.
From these two actions one can discern the outlines of a so-far undeclared GCC doctrine: the group will work together to preserve the status quo in all its member states. If there needs to be political change in the region, as in Yemen (which is not a GCC member), then it will happen with input from the GCC.
Of course, Saudi Arabia has for decades played a major role in Yemen. But acting under a GCC banner gives greater credibility. A Saudi plan would not be acceptable to many Yemenis, because of sensitivities at Saudi Arabia's big brother role in their country.
There is a clear need for the Gulf states to increase their cohesion and influence. But this requires them to boost their capacity for results-oriented diplomatic action. The Yemen plan is stuck. As a new report into the Yemen crisis by the Royal Institute of International Affairs in London points out: "The current stalemate reveals the GCC's limited leverage to negotiate a transition and, beyond that, to enforce implementation of any deal."
By inviting Jordan to join, the GCC could gain some useful military capacity. Jordan has long wanted to join the grouping, in the hope of exporting surplus labour and gaining cheap oil supplies.
The case of Morocco is not so clear. Its economy is tied more to Europe, and the distances are enormous.
What is clear, however, is that the invitation turns a regional grouping into a pan-Arab bloc of monarchies.
At first sight, the Arab world's monarchs seem to be the last leaders who need support. While all Arab states are affected by people power, the monarchies have proved themselves more stable than the republics, especially the "dynastic" pseudo-republics such as Egypt, Syria, Libya and Yemen, where power and succession are held by the president's family.
It is unlikely that the GCC states will instantly open their doors to visa-free entry for Moroccans, especially at a time when many of them need to get their own nationals into work. So the expanded grouping - some have called it "GCC Plus" - is clearly a political idea more than an economic one.
Commentators have criticised the expanded GCC as an alternative, or at least a counter-balance, to the Arab League. Since its inception, the Arab League has either been a vehicle for Egyptian policy, or it has been nothing. Continuing a long tradition, this year's Arab League summit scheduled for Baghdad has been put off for a year. A group of like-minded monarchies would certainly be more responsive and faster to agree than any currently conceivable line-up at the Arab League.
Some commentators have seen the idea of the expanded GCC as a reaction to Egypt's more accommodating stance towards Iran, which, if Cairo once again becomes the pace-setter in Arab politics, could set the tone for the Arab League. Unfortunately, a more likely scenario is that the divisions among Arab states will continue for the foreseeable future, and continue to paralyse the Arab League.
If this GCC expansion happens, it will take years and a lot of political will before the grouping becomes a real power broker. To rise to the demands of the moment and to accommodate new members, the GCC will require an expanded secretariat full of highly qualified people, and the members will have to get used to the fact that their club sometimes demands compromises that curtail their freedom of movement.
All this is necessary for the GCC to progress, but it is not going happen overnight.