President Obama supports the creation of a public insurance plan that would compete with insurers on state or regional marketplaces in which the uninsured and small businesses could buy coverage with the help of income-based subsidies. Most Republicans in Congress are against a public option, saying it would drive insurers out of business. And some key centrist Democrats in Congress say Democrats must give up on it if they want to win a filibuster-proof 60 votes in the Senate.