There’s something interesting in the full G20 statement:

19. We have agreed to support a general SDR allocation which will inject $250 billion into the world economy and increase global liquidity, and urgent ratification of the Fourth Amendment.

Interestingly $250B is exactly what George Soros called for called for on the 31st March. Note that he is one of Obama’s main backers.
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GS also said:
"I do not think America is ready to have the dollar replaced by SDRs as the international reserve currency," he said, but added: "In the long term it is something that may come in consideration and in the long term it may be in America's interest."

The ground work for that is now laid, that’s the curious reference to the 4th amendment.

The reference to ratifying the Fourth Amendment (of the IMF Articles of Agreement) means that Obama has agreed that the U.S. will vote to greatly expand the use of SDRs. They have always resisted this.

SDRs are the candidate to replace the Dollar as the global reserve currency.