ABC News’ Rick Klein reports:The Senate begins formal debate on health care today. And if it feels like we've been here before, that may be alright with Democrats who are pressing for final action before the end of the year. The chaotic past eight months on health care reform have been quite a show -- with town halls and tea parties, and countless threats and declarations from members of Congress. But, as Ezra Klein of The Washington Post pointed out on ABCNews.com's "Top Line" today, none of those spectacles have really changed the politics surrounding health care all that much. "It's amazing how much this has been very structurally decided. You would've known we were here if you'd tuned out for the last eight months," Klein told us. On one level, that's a statement on how much opinions are set on health care -- and how little the pleadings of politicians (up to and including President Obama) can shift those sentiments, and the votes of members of Congress. But the fact that reform efforts are still alive also seems to validate the White House strategy of conveying a sense of momentum for momentum's sake. "What I think the more surprising thing is, you haven't seen a collapse, right?" Klein said. "As for momentum, you know -- this thing just rolls forward." "It just sort of keeps steadily, gradually moving forward," he added. "What I'd really liken it to at the end is going to be [the] stimulus [bill]. I think that you're going to have it pass, but I think that by the end of it nobody's going to like it all that much -- that over time they'll be judged a success. But what happens is liberals are going to be furious about their concessions, Republicans will be angry about how much it spends. But it's one of those things where the legislative process, I think, makes everybody not like everything." Watch the full discussion with Ezra Klein HERE.