Associated Press: President Obamas determined efforts to combat global warming face their biggest trial yet as Republicans take full control of Congress this week. The GOP vows to move fast and forcefully to roll back his environmental rules and force his hand on energy development. The GOPs first order of business: the Keystone XL pipeline. The Republican-led House has repeatedly passed legislation to approve the pipeline, which would carry tar sands oil from Canada deep into the United States. The bills died...