PULLED APART by its historical ties with Russia and its government's ambition to join the European Union and Nato, Ukraine is in a precarious position following Moscow's military intervention in Georgia. Warnings of further Kremlin destabilisation of the Black Sea region have focused on Ukraine's mostly ethnic-Russian Crimea peninsula, where Russian and Ukrainian nationalists have clashed in the key port of Sevastopol, home to one of Moscow's most powerful naval fleets.
But the danger perceived by the United States and European Union, and the potential opportunity perhaps seen by an increasingly assertive Kremlin, has fostered anything but unity among Ukraine's pro-western leaders. As Washington and Brussels were trying to forge a united front against Moscow, following its recognition of the rebel Georgian regions of South Ossetia and Abkhazia, Ukraine's president and prime minister were re-igniting their bitter feud. Only months after the 2004 Orange Revolution propelled them to power and ousted pro-Moscow presidential candidate, Viktor Yanukovich, pro-western leaders Yulia Tymoshenko and Viktor Yushchenko were fighting each other, instead of implementing vital reforms. Mr Yushchenko sacked Ms Tymoshenko from the post of prime minister in 2005, but reinstated her last year, after her party's powerful showing in a general election - but it took only weeks for cracks in their relationship to reappear.
Now, Mr Yushchenko claims his erstwhile ally is trying to oust him with the help of Mr Yanukovich and his Kremlin-backed cohorts, while Ms Tymoshenko accuses the president of blocking vital privatisation and anti-corruption legislation. Both pro-western leaders believe the other is trying to undermine them ahead of the 2010 presidential elections. The usually strident Ms Tymoshenko, who has locked horns with Russia regularly over its controversial gas supply deal with Ukraine, has soft peddled on the Georgian conflict in an apparent attempt to woo Moscow and the millions of eastern Ukrainians who feel more affinity for Moscow than Kiev. Those residents of major industrial cities like Donetsk, Kharkiv and Odessa - as well and the often strident Russian nationalists of Crimea - must be won over if Ms Tymoshenko is to call herself a truly national Ukrainian leader, and to neutralise the power of Mr Yanukovich.
But in pursuing their protracted power struggle, Ms Tymoshenko and Mr Yushchenko risk damaging Ukraine's efforts to join the EU and Nato, and could encourage hawks in Moscow to try to destabilise the already restive Crimea. Visiting Kiev last week, US vice president Dick Cheney urged Ukraine's leaders to unite against the "threat of tyranny, economic blackmail and military invasion". His imprecations had no immediate effect in Kiev, however, and president and prime minister continue to trade allegations as tomorrow's EU-Ukraine summit hove into view. In-fighting at the top has scuppered any chances Ukraine had of receiving a fast-track invitation to join the EU or Nato. It must not be allowed to leave Crimea - or vital energy supplies to western Europe - vulnerable to Russian interference.