Politico: Environmentalists armed with new poll numbers have a warning for President Barack Obama: Approving the Keystone XL pipeline would put him at odds with core members of his base. The poll reveals an electorate deeply split on the Canada-to-Texas oil pipeline, which is wildly popular among Republicans and almost equally unpopular among Democrats. A small majority of people overall either support the project or dont know what to think, according to results provided to POLITICO. But the Center for...