When the Supreme Court ruled to uphold ObamaCare, Mitt Romney responded by vowing to repeal the president's signature domestic achievement, and to replace it with his own. However, Romney has given few hints of how he would actually address the serious deficiencies in America's health care system, which has left tens of millions of people without insurance, made medical emergencies the country's top cause of bankruptcy, and resulted in abysmal infant mortality rates for a developed nation, to take just one metric of public health. Romney's website has few specifics, but his past statements reveal a loose outline of where he stands on the issue, say Trip Gabriel and Robert Pear at The New York Times. Here, a guide to what health care would look like under a President Romney:

What are Romney's health care proposals?

Romney "would give a tax break to people who buy insurance individually on the open market," say Gabriel and Pear, so that they "would enjoy the same advantage as workers who get insurance as a benefit at work." Romney says he would take the federal government out of the equation, and leave it up to the states to figure out how to make health care more affordable. He also supports transforming Medicaid, the joint state-federal insurance program for the poor and the disabled, into a block-grant program, which would see the federal government give the states a lump sum of money with looser requirements on how they spent it.

Would these plans work?

It depends on what Romney's health care goals are. A presumably similar tax-credit plan from Sen. John McCain (R-Ariz.) in 2008 was estimated to increase the number of uninsured. Democrats say turning Medicaid into a block-grant program would only encourage local governments to purge their Medicaid rolls and use the money for other purposes. However, Romney's ideas "put more emphasis on controlling health costs and less on reducing the ranks of the uninsured, the primary goal of the Obama plan," say Gabriel and Pear. Without more specifics from Romney, it's impossible to calculate if his policies would result in lower health costs.

What about patients with preexisting conditions?

Romney says he would make sure those with preexisting conditions don't lose their coverage, but opposes a provision in ObamaCare that makes it illegal to deny them coverage. Romney also would not require insurance companies to allow children to stay on their parents' plans until they're 26. Those two provisions are among the most popular elements of ObamaCare.

Why is he reluctant to put out a plan of his own?

Romney "has spent much of the presidential campaign shying away" from the subject, says Kasie Hunt at The Associated Press, because of the health care law he passed as governor in Massachusetts. RomneyCare is very similar to ObamaCare, replete with an individual mandate requiring nearly all citizens to buy health insurance. As a result, any discussion of health care invariably raises uncomfortable questions about why Romney suddenly opposes a mandate. That has left Romney with a "huge void" when it comes to replacing ObamaCare, and his campaign "calculates it can finesse until after the election," says Albert R. Hunt at Bloomberg.

Has RomneyCare created other political problems?

Yes. Republicans have seized on the Supreme Court's interpretation of the mandate as a tax to hammer Obama for raising taxes. (Democrats maintain that it is a penalty for failing to buy insurance, not a tax.) However, conflating a mandate with a tax would mean Romney himself raised taxes as governor of Massachusetts. On Monday, Romney's top aide, Eric Fehrnstrom, argued that the mandate is not a tax, straying "wildly from the coordinated comments" of Republicans in Congress, says Michael D. Shear at The New York Times.

Sources: Associated Press, Bloomberg, The Huffington Post, Investopedia, The New York Times (2), The Washington Post

Read more political coverage at The Week's 2012 Election Center.