It amazes me that the AARP seems to be on the Obamacare train.
No one argues that any public health system will have to carefully consider where to apply its limited funds. One obvious place to cut back will be care for the elderly. When put into pretty much any equation, those who've already had many decades, who have few years ahead of them at best, and who have many health issues will be seen as a poor investment of healthcare dollars.
Of course, the other big issue is that, even when care is not denied, it will be substandard simply because of wait times, poorly trained physicians, and limited access. The latest horror story out of Britain's healthcare system has people getting arthritis drugs only after it's too late to do them any real good.
If you're old or ever will be, and if you care about anyone who is, I would advise asking your Congressmen to hold out for something else than nationalized healthcare.