Maine GOP Sen. Susan Collins is unlikely to back the Republican Party's latest push to repeal Obamacare, she said Sunday, but is waiting for more information from the Congressional Budget Office before finalizing her opinion.Collins, appearing on CNN's "State of the Union," said it was "very difficult for me to imagine a scenario" where she votes for Graham-Cassidy, which would repeal large chunks of Obamacare and replace it with block grants to the states.