The presidential contest currently under way in the US has generated unprecedented interest in the UK and Europe. Were it left to us on this side of the pond, Barack Obama would win with a landslide. On account of his youth, his colour and his relatively liberal views, Obama is the darling of Europe's liberals, while not only they, but also European conservatives widely look forward to his presidency as a welcome departure from the hawkish, abrasive unilateralism of George W. Bush's administration. Yet while Obama as US president would be likely to go down well with the European and, indeed, the world public, this would above all be for the negative reason that - like Clinton before him - he probably would not do very much in the field of foreign affairs. By not rocking the boat or rapping knuckles, a President Obama would appease European liberals and conservatives alike. But by the same token, he may prove inadequate in meeting very real threats to peace and stability in Europe. Nowhere are these threats more real than in the south-eastern borderlands of our continent: the Balkans, Turkey and the Caucasus.

So popular a hate figure has the unilateralist US hawk become among our chattering classes, that it is widely forgotten just how much damage was done by Clinton's dovish, multilateralist, do-nothing approach to foreign policy - not only to global peace and security, but to democratic Europe's relations with the US. Coming to power as a critic of Bush Senior's inactivity over the bloodbath in Bosnia, Clinton, in the face of the determination of his European allies to avoid military action and to appease Serb aggression, quickly backed away from his electoral promise of tougher action. The result was the worst crisis in US relations with Britain and France since Suez, as Clinton vacillated between Congressional pressure for intervention in defence of Bosnia on the one hand, and Anglo-French resistance to intervention on the other. Where decisive US leadership was needed, the Democratic president was lacking. In summer 1995, Clinton did belatedly opt to intervene against the Bosnian Serbs, and then the Europeans quickly fell into line and the Bosnian war was brought to an end, but only on the basis of the unprincipled Dayton settlement that has bedevilled regional stability ever since.

Clinton enjoyed advantages in the global arena unprecedented for a US leader since Roosevelt, most notably the absence of a Russian threat. But rather than take advantage of the opportunity of the Soviet collapse to reshape Eurasia, he sat back and allowed the Russians to dismember Georgia, and tacitly supported their brutal assault on Chechnya in 1994. He did not predict that a Russia capable of employing such murderous violence against its own, Chechen civilians would likely prove a danger to the West in the long run, or that, fifteen years later, a beleaguered Georgia would represent the threatened frontline before this threat. So, as in other parts of the world, the Bush Administration in South East Europe has had to try to clear up the problems left unresolved by its predecessor. And it has done so with some success: NATO expansion has been accelerated and US relations with former Communist bloc countries boosted; Kosovo's independence has been recognised; Macedonia has been recognised by the US under its constitutional name; and cooperation with Georgia has been strengthened.

Nevertheless, the next US president will have a much more difficult job managing South East Europe than either Clinton or Bush was faced with. The principal reason for this is the resurgence of Russian aggressiveness and power under Vladimir Putin. Moscow has successfully prevented a resolution of the Kosovo problem, keeping this sore festering and bolstering Serbia's self-destructive determination to keep the Balkans permanently on the brink of a new conflagration. Moscow has reignited its dormant conflict with Tbilisi over the breakaway regions of Abkhazia and South Ossetia, making war between Russia and Georgia more likely than at any time since the early 1990s. And it has embarked upon a sustained campaign to obstruct and derail NATO's eastward expansion. The next US president will be faced with a dangerous opponent in South East Europe, one that Clinton did not have.

Unfortunately, just as the threat posed by Russia and its satellites is greater than ever, so democratic Europe's commitment to regional progress has weakened as the West European powers have regressed back toward more short-sighted, selfish policies. Germany is building an axis of its own with Russia, at the expense of the unity of the Western alliance and in contempt of the feelings of Poland and other states that have traditionally had reason to fear an axis of this kind. France under Nicolas Sarkozy is pursuing a traditionally Gaullist policy of apparently gratuitous bloody-mindedness, one that appears calculated to upset regional stability and undermine the US and NATO - almost as ends in themselves. At the NATO summit in Bucharest in April, Germany and France defied the US to veto the granting of Membership Action Plans to Georgia and Ukraine, weakening the ability of these two frontline states to resist Russian bullying. Germany and France also backed Greece in its successful effort to keep Macedonia out of NATO, on account of the unresolved ‘name dispute' - a staggeringly irresponsible blow against a fragile, ethnically divided state whose collapse would bring regional cataclysm. Paris is also reverting to its traditionally pro-Serbian policy in the Balkans, undermining any possibility that Belgrade can be pressed to adopt a more responsible attitude vis-a-vis Kosovo.

Bush was also faced with obstruction from France and Germany, something that is often wrongfully attributed to their opposition to the Iraq war, though this has been more an excuse than an actual reason for Franco-German mischief-making. But Bush at least has had the benefit of constructive support from some key allies. The next US president will have less of this. Turkey, the US's most important ally in the region, has been under the constructive rule of the Justice and Development Party (AKP) for the best part of the 2000s. Yet the country is currently undergoing an internal upheaval that could result in a judicial coup d'etat by anti-democratic elements in the old, Kemalist establishment determined not to share power with the new middle class represented by the AKP. This could lead to a turn by Turkey toward an ultra-nationalist, anti-Western path; its realignment with Russia, China and/or Iran; and possibly even a civil war on the Algerian model. These dangers are increased by the Franco-German determination to keep Turkey out of the EU; Paris and Berlin appear less concerned with the geopolitical dangers of abandoning Turkey than they are with maintaining their dominance within the EU and pandering to the anti-Islamic sections of their electorates.

Meanwhile, while Britain under Blair was a stalwart ally of the US on every front that mattered, Brown has been a disappointment in this regard, appearing scarcely to have a foreign policy worthy of the name. At Bucharest, he failed to stand alongside the US in defence of Macedonia, Ukraine and Georgia, and his one initiative of note with regard to the region has been a wrong-footed statement in support of the Greek Cypriots, that appears dangerously to indicate a retreat from the UK's traditional support for Turkey. The one major West European state upon which the US has traditionally been able to rely - except under John Major's disastrous Conservative government - is no longer a known quantity.

In sum, in the years to come, the burden of defending Western interests and values in the region stretching from the Adriatic to the Caspian and from Ukraine to the Iraqi border will fall more heavily on the US's shoulders alone. And it is precisely at this moment that we are faced with the prospect of an Obama presidency.

The dangers of this are twofold. The first is that, at the very moment when there is greatest need for US leadership, and for more US unilateralism to compensate for Europe's retreat into short-sighted selfishness, a President Obama would defer to the West Europeans on issues relating to South East Europe, on account of his own inexperience and lack of interest in foreign affairs. This is precisely what Clinton did, but in Obama's case, there is the additional incentive of desiring to be seen to break with the diplomatic style of the Bush Administration. Obama's policy statements over Iraq, Iran, Pakistan and Israel show all the hallmarks of a politician who sees foreign policy solely through the prism of his domestic popularity, and who flip-flops between wanting to appear hawkish and wanting to appear dovish. Such a president would be highly unlikely to overrule narrow-minded but stubborn West European governments over a part of the world that does not readily excite American public imagination; nor is it certain he would stand up to Russia when necessary.

The second danger is less certain, but potentially greater: it is that Obama is genuinely sympathetic to trouble-making elements in South East Europe. As recently as August 2007, Obama sponsored Senate Resolution 300 in support of the Greek position on the Macedonian name dispute - this after the Bush Administration had already wisely recognised Macedonia under its constitutional name. In a letter to the Serbian Unity Congress, an arm of the US's Serb lobby, following international recognition of Kosovo's independence in February, Obama appeared to endorse the Serbian position on Kosovo - that rejects any solution to the Kosovo question, such as independence, that is not acceptable to both sides. According to US analyst John Sitilides of the Woodrow Wilson Centre, Obama is politically sympathetic to Serbia, partly on account of the large Serb community in his state of Illinois. Obama has recently appointed Lee Hamilton as his foreign policy advisor; Hamilton has received funding from the leaders of both the Greek-American and Serb-American communities in the US. Obama has also prominently supported US Congressional recognition of the Armenian genocide, a move that would damage US relations with Turkey and strengthen the hand of Turkish anti-Western, ultra-nationalist elements (Turks may legitimately wonder why, of all the historic cases of genocide, it is this one alone that inspires the activity of certain US Congressmen, who meanwhile show no readiness to recognise the historical genocidal crimes of which Ottoman Muslims were victims). All this could be rationalised simply as Obama's attempts to maximise his votes among Greek-American, Serb-American and Armenian-American voters, but it does not bode well for the policy his administration would adopt toward South East Europe.

McCain, by contrast, was a champion since the 1990s of the rights of the Kosovo Albanians, at a time when right-wing Republicans - whether out of hostility to Islam or hostility to Clinton - were widely supportive of Belgrade. Although far from uncritical of Turkey, he has indicated his awareness of its strategic importance, including vis-a-vis Iraq, and opposes Congressional recognition of the Armenian genocide as something that would needlessly damage the US's relations with a key ally. Finally, McCain led a delegation of US Congressmen to Tbilisi in 2006, to express unconditional support for Georgia's territorial integrity and to challenge the presence of Russian ‘peacekeepers' in South Ossetia.

McCain's approach to these issues is to some extent characteristic of a liberal Republican hawk, as distinct from a relatively dovish Democrat like Obama. But the difference between the two is also the difference between an older, more experienced politician with a keen interest in foreign policy and a global vision, and a younger and less experienced newcomer who still sees foreign policy through the prism of domestic political concerns. If Obama wins the US presidential election; if the policy of the EU states toward South East Europe continues to degenerate; if Russian policy continues along its current aggressive trajectory; and if another regional conflagration results, we may soon come to regret that the more unilateralist candidate did not win.