Karl Rove argues that a "public" insurance option will cause individuals and companies to drop private insurance and switch to the "public" plan:

They'd be happy to shift some of the expense -- and all of the administration headaches -- to Washington. And once the private insurance market has been dismantled it will be gone . [E.A.]

I must be missing something--why would the collapse of private health insurance be irreversible? It can't be that hard to start a private insurance company--it's not like starting a private nuclear power company or even an auto factory. If we enact a public plan, but at some point in the future a potential market for private insurance opens up--maybe because Republicans win huge congressional majorities and decide to end government-run insurance--private insurers will spring up to make money in that market, no?...

P.S.: Rove's pet Bush-era plan to buy Hispanic votes with a giant semi-amnesty of illegal immigrants--now that would be irreversible. ...