Check this line from Mercer:
South Dakota already operates a risk-pool program for people who had insurance but lost it through no fault of their own. Rounds, who runs an insurance business, started the state risk pool to reduce financial responsibility of insurance companies which were pulling out of the health-coverage market in South Dakota [Bob Mercer, "State Picks and Choose on Federal Health Coverage Law," Pure Pierre Politics, 2010.07.01].
Mercer doesn't reach this conclusion, but I do: Governor Rounds and fellow defenders of the free market don't want the free market to handle all of health coverage... only the really profitable portions. They thus are happy to saddle the government with the elderly, the poor, and the sick folks who need health insurance the most. The insurance companies thus limit themselves to the young, rich, and healthy whose minimal use of health services guarantee that the house always wins in the private insurance casino.
The high-risk pool is really a safety valve for private profit. Until the ban on exclusions for pre-existing conditions kicks in in 2014, private insurers can continue to kick sick people off their plans without any prick to their conscience: "Those people won't suffer. They can just join the government high-risk pool! Besides, we're here to serve our shareholders, not the common good."
I wonder how long we'll watch this patchwork system hobble along, bankrupting and killing Americans all for the sake of protecting profit and a failing worldview, before we realize it would be a whole lot simpler for us to create one big risk pool.