As part of their giant tax bill, Republicans in Congress are about to eliminate the Affordable Care Act's individual mandate. Their objective is not sensible health care reform but rather insensible arithmetic that could satisfy the byzantine rules governing the Senate's reconciliation process.
The purpose of the mandate is to evenly distribute risk among healthy and unhealthy Americans on the individual insurance market so that costs are shared and no one is left out.
Will killing the mandate ruin Obamacare exchanges? No, but it will transform them into an extended form of Medicaid by another name. Americans with subsidized policies will stay in the system, with help from the federal government.