Reuters: U.S. President Barack Obama has backed a plan by the host of next month’s climate change talks in Copenhagen to seek a political deal and leave legally binding decisions for later, a U.S. official said on Sunday. "There was an assessment by the leaders that it was unrealistic to expect a full internationally legally binding agreement to be negotiated between now and when Copenhagen starts in 22 days," a top U.S. negotiator, Michael Froman, told reporters. With Kyoto’s first …