I just don't see how the bill can stand without the mandate. Without the mandate, the whole thing crumbles. Just at first glance, take the prohibition against insurance companies discriminating against "pre-existing conditions" into consideration. There is no possible way to fund that provision without the mandate. It is the only mechanism in ObamaCare that addresses that specific and massive influx of uninsured people into the system. Take away the mandate and keep the pre-existing condition provision, and there will be a flood of people dropping their insurance, and every insurance company in the country will be bankrupt within the month.
It seems to me that if ObamaCare fails, that failure will reside in the political reality that the mandate was crafted as a substitute for the power to level a tax, at a time when such a massive tax increase was politically untenable. If the funding mechanisms for this bill were built on the federal government's power to tax, I think it may have been unstoppable. But that kind of tax increase was never going to happen. In the end, if this falls, in hindsight it will appear that the best the Leftists could do was cram through something that would give their hardcore base a new "hill" to fight for. They've certainly upped the stakes and clarified the issue, if nothing else.