ISTANBUL (Reuters) – President Tayyip Erdogan has developed strong economic and political relations with both Moscow and Kyiv in recent years, which leave Turkey facing a delicate balancing act in its response to the Russian invasion of Ukraine. Ankara cannot afford to fall out with Russia economically because of tourism revenues, gas supplies, grain and other agricultural trade, and a nuclear power project. The rival positions Turkey and Russia have taken in wars from the Middle East to the Caucasus mean it must also tread carefully to avoid widening fault lines in their awkward alliance. Gro…