The subsidized insurance program at the heart of Massachusetts' healthcare initiative is expected to roughly double in size and expense over the next three years. Thisn unexpected level of growth could cost state taxpayers hundreds of millions of dollars or force the state to scale back its ambitions. The state has asked the federal government to shoulder roughly half of the program's cost from 2009 through 2011, but there is no guarantee of that funding. The Commonwealth Care program provides free or subsidized insurance for low- and moderate-income residents.