According to a new study by the KaiserFoundation and the Urban Institute, states fully implementing Obamacare’s Medicaid expansion would result in an additional 21.3 million Americans on insurance rolls while raising states’ Medicaid spending by less than 3%.

Since the federal government will pick up most of the tab for the Medicaid expansion, the states that choose to participate will be able to extend insurance to millions of poor and vulnerable Americans without using much of their own funds. In fact, the study finds that states will receive more than $9 from the federal government for every $1 they invest in their Medicaid programs. Even the GOP governors against reform would see a net budgetary gain from the expansion through lower uncompensated care costs and a healthier population.