During an interview with Fox News Brett Baier, Speaker of the House Paul Ryan explains [06:00 portion] how the ObamaCare replacement bill is currently being written:

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Staying out of the weeds – why this is important. Inherent within this Ryan outline is the admission there was never a replacement bill for Obamacare before today.
Why is that important?
Because the admission proves that prior to President Trump there was no ACTUAL republican intention, an actual legislative position, to remove Obamacare.
Oh yeah, and it also proves Ryan lied to Hannity when he said the bill was currently being scored by the Congressional Budget Office (CBO). Huh, funny that.
Again, this evidences what we previously outlined when we said to repeal ObamaCare you must first remove The Big Club.
The Big Club, lobbyists and bureaucrats, actually write the legislation. The politicians simply sell the legislative constructs written by Lobbyists who are part of the Big Club.
The Big Club didn’t expect to lose the 2016 presidential election; either Jeb Bush or Hillary Clinton would have maintained the legislative priorities of the Big Club. Now, as a specific outcome of Trump winning, Paul Ryan is actually having to create/write legislation that is necessary only because President Trump is looming over his shoulder.