President Obama’s confirmation that the United States would begin arming Syrian rebels has prompted an urgent debate about both the legality and the effectiveness of the decision. It followed a joint statement two days earlier by the US secretary of state, John Kerry, and the UK foreign secretary, William Hague, that their priority remains to see a diplomatic process “that succeeds in reaching a negotiated end to the conflict”.

What apparently shifted the US position from staying on the sidelines to becoming a more direct participant in an increasingly vicious proxy war was its own assessment that the Assad regime had crossed the “red line” by deploying chemical weapons. Welcoming this US assessment, Hague reiterated the need “to save lives, to pressure the Assad regime to negotiate seriously, to prevent the growth of extremism and terrorism, and to stop the regime using chemical weapons against its people”.

Leaving aside the question of whether any of these objectives can be achieved by arming the rebels, another puzzle is why Syria has become such an important battleground for various outside players.

Last week, I argued on The Conversation that “Syria is a likely catalyst for … a regional escalation and a definite battlefield for the proxy wars already happening”. The local and regional escalation of the civil war in Syria that is sure to occur following Obama’s decision to provide military aid to the rebels will only make this more obvious.

While there is undoubtedly a humanitarian impulse behind the US decision (after all, a vast number of people, predominantly civilians, have been killed, displaced, and turned into refugees), Syria’s geo-strategic position is such that the US and its Western allies have clear interests in the outcome of the Syrian civil war. At the top of the list is the prevention of a spill-over into Israel, Iraq and Turkey (the latter two already at risk of increasing domestic instability). The West is also conscious of wanting to contain – and roll back – Iranian influence (the Cold War analogy is obvious, albeit not too fitting). In addition, there is, as noted by William Hague, understandable concern about the potential for “the growth of extremism and terrorism”.

These objectives are, in part, shared by others. Saudi Arabia is equally keen to prevent an expansion of Iranian (and Shia) influence across the region. With an increasingly pro-Iranian regime in Iraq, Tehran’s geopolitical reach now extends contiguously to the Mediterranean, linking it also more easily to one of its main regional power levers, Hezbollah in Lebanon. There is, of course, also an economic dimension to this “axis” Tehran-Baghdad-Damascus. Stability along this route makes the prospects of Iraqi oil and Iranian gas exports via the Mediterranean more viable. Syria could additionally reap significant benefits as an important transit country if a 2011 trilateral agreement between Iran, Iraq and Syria on a pipeline were to be realised.

Riyadh’s battle with Qatar over the make-up of the Syrian opposition leadership is about dominance in the Gulf Co-operation Council and the Arab world as much as it is about Saudi fears that strengthening radical, al-Qaeda-linked elements among the anti-Assad opposition will eventually backfire and undermine incumbent regimes elsewhere in the region, including the House of Saud.

While Israel has so far taken a relatively defensive position, it shares concerns over Iran and Hezbollah. Moreover, neither Israel nor the US and its others Western allies can have any interest in further Islamist radicalisation in Syria given the disputed and potentially highly volatile nature of Israel’s borders with Syria along the Golan heights. Arguably, too, none of the other states in the region have any interest in a military escalation on that front either as it could quickly embroil them in an unprecedented new regional war.

Russia has emerged as the other main external supporter of the Assad regime, alongside Iran. But much like every other outside player, Russia is pursuing its own national interests of retaining a regional presence, asserting influence in a geo-strategically important part of the Middle East and curbing what it sees as a Western-driven agenda of regime change. Given its own fears about Islamic extremism, Russia in all likelihood shares the Western objective of preventing Syria from becoming a home for future global jihadists.

However, unlike the West, Russia considers backing the current regime, rather than arming so-called moderate rebels, a more viable prospect in achieving this. In Russia’s approach, Assad is, at present, a convenient ally, but he is expendable as soon as a more viable option emerges. Russia’s alliance of sorts with Iran is also more one of convenience than anything else.

Russian political and military support of the Assad regime, thus, in many ways is tactical. Its efforts (genuine or not) for a peace conference also need to be seen in the context of its desire for a better-managed transition process in Syria that will see Russian interests protected.

Where does all this leave Syria and its people? The short answer is “on their own”. The pursuit of self-interest by powerful outsiders overlaps only marginally with what Syrians need in order to achieve an end to the violence they have suffered for more than two years now. The US decision to arm the rebels is unlikely to make peace possible anytime soon. But that said, not arming them would not have brought us closer to a just and stable peace in Syria either.

(This analysis also appeared in The Conversation.)