Romney also has criticized Obama for over-regulation on environmental issues. That covers many areas, but the biggest difference involves global warming.
Climate change, like healthcare, is an issue on which Romney's positions have changed almost entirely. As governor, particularly early in his tenure, he viewed climate change as a priority and pushed an ambitious plan to reduce Massachusetts' emissions of carbon dioxide and other greenhouse gases that drive global warming.
In his 2010 book "No Apology: The Case for American Greatness," Romney wrote: "I believe that climate change is occurring — the reduction in the size of global ice caps is hard to ignore. I also believe that human activity is a contributing factor."
In his campaign, however, he has avoided the issue, giving deference to the skepticism that many Republicans express about whether global warming is a real phenomenon. He has promised to push amendments to the Clean Air Act to end the Environmental Protection Agency's power to regulate greenhouse-gas emissions.
Obama made global warming a significant issue in his 2008 campaign. The administration's major effort on that front, the cap-and-trade bill, passed the House in 2009 but failed in the Senate.
That proposal would have set an overall ceiling on the amount of carbon dioxide that the U.S. economy could produce. The cap gradually would lower, and industries would be allowed to buy and sell permits allowing them to emit carbon dioxide. The idea is that free trading of permits would allow the market to find the least expensive ways to reduce emissions.
In the absence of new legislation, the administration has taken two major regulatory steps to combat global warming. Last year, the administration reached agreement with automakers on a plan that would significantly raise the fuel economy of new U.S. cars, reducing carbon dioxide emissions as a result. Earlier this year, the EPA proposed new rules that would limit emissions by power plants — effectively eliminating nearly all new coal-fired plants.
Obama has not said whether he would push the EPA to take more regulatory actions to limit carbon dioxide emissions in the future if Congress adopts no new legislation.
Romney has said he would seek to roll back the higher fuel economy standards for 2017-2025, which he has labeled unrealistic. He has accused the administration of "waging a war on coal" and has said he would seek to increase coal usage.
The Obama and Romney campaigns accuse each other of being "out of the mainstream" on U.S. foreign policy, but despite heated rhetoric, the two candidates have enunciated few significant policy differences. Given the similarities, the real choice for voters is a more subjective one — which man would better achieve the foreign policy goals that both espouse.
Throughout the Obama years, a fault line has run through the Republican Party on foreign policy. On the one side are people, many of them associated with the George W. Bush administration, who believe the U.S. should use its military power more often to back groups that claim to support democracy.
Sens. John McCain (R-Ariz.) and Lindsey Graham (R-S.C.), for example, have criticized Obama for not intervening more forcefully in Syria and for setting a firm withdrawal date from Afghanistan. Both also criticized the administration's efforts in Libya as insufficient, although that criticism died down once the effort succeeded in topping the regime of Col. Moammar Kadafi.
On the other side, many Republicans have argued for less U.S. involvement overseas. The most prominent person on that side of the debate has been Rep. Ron Paul (R-Texas). But many Republican elected officials who did not back Paul's presidential campaign nonetheless supported a proposal last year to end U.S. involvement in the Libya mission.
Romney has not resolved that tension within his party and has sometimes appeared to go back and forth between the positions of the two camps. On Afghanistan, for example, Romney initially attacked Obama for setting a 2014 deadline for withdrawal, saying it would embolden the Taliban. Democrats attacked him for advocating a lengthier U.S. commitment to the war.
More recently, Romney has said that he too would withdraw all troops on the same schedule Obama has used or, as he put it in his recent speech at a Veterans of Foreign Wars convention, "complete a successful transition to Afghan security forces by the end of 2014."
On Iran, Romney has attempted to sound tougher than Obama without seeming to commit the U.S. to a war. As Obama has gradually toughened his own language, the two have arrived at a virtually identical position — arguing for strong sanctions backed by a threat of force to try to get Iran's leaders to back away from their nuclear ambitions.
Romney has also sharply criticized Obama for his Middle East policies, saying that he has been disrespectful of Israel. On his late-July trip to Jerusalem, Romney made rhetorical nods to conservative supporters of the Jewish state, who are among his largest financial backers. In speeches, he referred to Jerusalem as Israel's capital. That cheered those who would like the U.S. to move its embassy to Jerusalem from Tel Aviv. He also pointedly did not mention support for a Palestinian state.
But before leaving Israel, Romney gave an interview to CNN in which he tacked back, saying that he supported two separate states for Israelis and Palestinians and that moving the U.S. embassy was a goal to achieve "ultimately."
More recently, Romney has accused the Obama administration of mishandling the unrest that broke out in the Middle East after a video impugning Islam that was produced by a California man began to circulate on the Internet.