Democratic leaders unveiled a proposal on Wednesday aimed at reducing college-education costs and increasing the number of college graduates by one million in the next 10 years. The plan, which the Democrats dubbed Saving the American Dream, proposes to give $150-billion over the next decade to states in block grants whose sizes would be determined by the number of students who attend and graduate from their public colleges. Under the proposal, all families that put students through college, graduate school, or training could receive a $3,000 college-tuition tax credit. The credit would cover up to four years of such education; families too poor to owe taxes would receive it in the form of a refund. The tax credit, if adopted, would replace other higher-education tax breaks.