Washington (CNN) – A new national survey of Republicans indicates that it's basically all tied up between Mitt Romney and Newt Gingrich in the race for the GOP presidential nomination, with Gingrich on the rise and businessman Herman Cain falling due to the sexual harassment allegations he's been facing the past two weeks. According to a CNN/ORC International Poll released Monday, 24% of Republicans and independents who lean towards the GOP say Romney is their most likely choice for their party's presidential nominee with Gingrich at 22%. Romney's two-point advantage is well within the survey's sampling error. While the level...