The Obama administration's plan for U.N. climate change talks encountered swift opposition after its release Tuesday, with Republican leaders warning other countries to "proceed with caution" in negotiations with Washington because any deal could be later undone. Republican critics say the administration lacks the political and legal backing to commit the United States to an international agreement. Some observers said that resistance to the administration's climate policies leaves foreign governments questioning whether Obama's commitments can last. --Valerie Volcovici, Reuters, 1 April 2015
