By Darren Parkin US President Joe Biden is expected to meet on Tuesday with congressional leaders for emergency talks on the debt ceiling limit as the US barrels toward a deadline that could come as soon as June 1. The negotiations are to avoid what could be an unprecedented default that would rock the global financial system. Biden has been reluctant to give details about terms of the talks but said at the weekend that he believed a deal could be reached. The standoff is down to Democrats demanding a “clean” increase without conditions to pay debts resulting from spending and tax cuts approve…