In the face of projections that an ACA repeal would cause millions to lose coverage, some congressional leaders have called for a multiyear transition period—during which the law’s insurance reforms and subsidies would remain in place. But as Georgetown Health Policy Institute's Sabrina Corlette and Kevin Lucia and the Wakely Consulting Group's Julie Andrews point out, the uncertainty that arises from this transition period, along with a tight timeline for bringing health insurance products to market, would likely create major disruptions.