"It is an illusion for members of Congress to think that they can vote this plan down and then turn around and still persuade countries like China, Japan, South Korea, Turkey, India - Iran's major oil customers," Kerry said in yet another passionate plea on Iranian nuclear deal in Philadelphia.
"They ought to continue supporting the sanctions that are costing them billions of dollars every year? That is not going to happen," Kerry said.
"We don't have that money. We can't control it. It is going to begin to be released, anyway, if we walk away from this agreement. Remember as well that the bulk of the funds Iran will receive are those that sanctions relief are already spoken for, and they are dwarfed by the country's unmet economic needs. Iran has a crippled infrastructure, energy infrastructure, it has got to rebuild it to be able to pump oil," he said.
More From This Section
"But we do know what Iran says it will do, and that is begin again to expand its nuclear activities. And we know that the strict limitations Iran has accepted will no longer apply, because they will no longer be any agreement," he said.
"Iran will then feel free to begin operating thousands of other advanced and other centrifuges that would otherwise have been mothballed. They will be free to expand their stockpile of low enriched uranium, rebuild their stockpile, 20 per cent enriched uranium, free to move ahead with the production of weapons-grade plutonium. Free to go forward with weaponisation research," said the top American diplomat.
Latest figures indicate that the Obama administration is inching towards support for the deal in the Senate.
"The Iran agreement is not a panacea for the sectarian and extremist violence that has been ripping that region apart, but history may judge it as a turning point, a moment when the builders of stability seized the initiative from the destroyers of hope, and we - when we were able to show, as have generations before us, that when we demand the best from ourselves and insist that others adhere to a similar high standard, when we do that, we have immense power to shape a safer and a more humane world," Kerry said.