The debate over social programs that has become a dominant theme of the presidential race is all about the future of Medicare. But the outcome of the election will probably have a more immediate and profound effect on Medicaid, the state-federal program that provides health care to poor and disabled people.

Few other issues present a starker difference between the Republican and Democratic tickets. President Obama, through the health care law, seeks an expansion of Medicaid, which covers more than 60 million Americans -- compared with 50 million in Medicare -- and costs the states and the federal government more than $400 billion a year.

The president envisions adding as many as 17 million people to the rolls by allowing everyone with incomes up to 133 percent of the poverty level to enroll, including many childless adults. While the Supreme Court ruled in June that states could opt out of the expansion, Medicaid -- and federal spending on it -- is still likely to grow significantly if Obama wins a second term.

Romney and Ryan would push for the repeal of the health care law and replace Medicaid with block grants, giving each state a lump sum and letting them decide eligibility and benefits. In pure dollar terms, the difference comes down to this: As chairman of the House Budget Committee, Ryan has proposed cutting federal spending on Medicaid by $810 billion over 10 years, largely from repealing the health care law. Obama's expansion plan would cost an additional $642 billion over the same period, the Congressional Budget Office said.

Proponents of the Republican plan for Medicaid say block grants would be the best way to curb Medicaid spending and make the program more efficient. But critics of the block grant plan say it would inevitably shrink the medical safety net for the poorest Americans. The Urban Institute, a nonpartisan research group, estimated that under a similar House budget proposal last year, 14 million to 27 million people could lose Medicaid coverage by 2021.



President Obama would make tax credits for college expenses permanent and expand Pell grants for students from lower-earning families. Mitt Romney would emphasize the need to curb rising tuitions and federal education expenditures.

Obama would let the current $5,550 per year maximum Pell grant increase to $5,635 next year, as scheduled. That figure has grown by more than $900 since 2008 for a program that is the largest source of federal aid for students, serving more than 9 million of them. He would make permanent the American Opportunity tax credit, created as part of his 2009 economic stimulus program. The credit provides up to $2,500 a year per student for college costs but is due to expire Jan. 1. Renewing it would cost an estimated $13 billion next year alone.

Romney said he would eliminate duplicative federal college financial aid programs and direct Pell grants to "students that need them most." He would also put private lenders back in the business of issuing federally backed student loans. When asked by a voter what he would do to make college more affordable, he replied that while it might be popular for him to answer that he would provide students with government money, "what I'm going to tell you is shop around."



Mitt Romney, who is trying to gain an edge with a disputed charge that President Obama is giving welfare recipients a free ride, can point to his own record of pushing for tighter rules during his tenure as governor. Romney fought to require single parents with children as young as 1 to work to get welfare benefits if they could obtain state-subsidized child care. He also opposed efforts to allow time spent in job training or education programs to count toward the state's 20-hour weekly work requirement, and pushed for a five-year lifetime limit on welfare benefits. However, he also tried to shield welfare benefits from budget cuts as the state struggled with sinking revenues.

Romney's campaign alleges that Obama is loosening welfare restrictions by ending a provision that requires welfare recipients to work. The White House says the waivers Obama approved for states would only allow them to drop the work requirement if they can accomplish the same goals using different methods.