If there was any doubt that Chuck Schumer, the senior senator from New York, is one of the most influential powerbrokers on Capitol Hill, it evaporated late on Monday night.

Just minutes after news broke that Citigroup would receive a $7.5bn (€5bn, £3.6bn) injection from the Abu Dhabi Investment Authority, Mr Schumer blessed the investment in a press release that included Citigroup's own announcement of the deal.