Medicare buy-in is seen as a moderate proposal, but it would set off a domino effect of cost shifting that would leave few people untouched. It would mean that services for more people would be covered by insurance that reimburses providers at below-cost Medicare rates, placing more pressure on providers to negotiate higher rates with private insurers to offset the loss in income. Such a shift would place upward pressure on individual market premiums.  Providers would also try to limit the number of Medicare patients they see, making it more difficult for today’s seniors as well as the buy-in populations to access care.