Group of Seven (G7) leaders start their annual summit on Thursday looking to double down on support for Ukraine in its war with Russia and offer a united face in confronting China’s political and economic ambitions. With the Middle East, migration and artificial intelligence (AI) also on a packed agenda, the June 13-15 summit in southern Italy would be taxing for leaders at the best of times, but most of them are also bowed down by their own domestic woes. US President Joe Biden, facing a tough re-election bid in November, arrived in Italy the day after his son Hunter Biden was convicted of ly…