Tonight's third and final presidential debate is scheduled to focus on foreign policy. But in doing so, President Obama and Gov. Mitt Romney will likely address a decidedly domestic issue – gas prices.

Throughout the fall campaign, Romney has criticized Obama over the increase in gas prices that has occurred over his White House tenure.

That's true. Gas prices did indeed rise over the course of Obama's presidency. At best, however, that charge offers a surface glance at a complex issue. Heading into tonight's debate in Boca Raton, Fla., here's what you need to know:

Today, the national average for a gallon of regular unleaded fuel is $3.67, according to GasBuddy.com. The average has fallen 15 cents in the past month.

On Nov. 4, 2008, Election Day, the national average stood at $2.35 per gallon.

On Jan. 20, 2009, the day of Obama's inauguration, the national average had dropped to $1.82, according to GasBuddy.com.

What you'll hear from neither candidate tonight is that experts agree that the President of the United States doesn't have much control over the price of gas. Global demand drives the price of oil and gasoline.

"The reality is that presidents have very little to do with near-term fluctuations in gasoline prices," Frank Verrastro, the director of the energy program at the Center for Strategic and International Studies said while testifying before a U.S. Senate panel earlier this year.

Richard Thaler, a professor of economics and behavioral science at the University of Chicago says it's "wishful thinking" that either candidate could affect gas prices.

In a survey conducted by his university, 41 economists of varying political views were asked to agree or disagree with the following statement: "Changes in U.S. gasoline prices over the past 10 years have predominantly been due to market factors rather than U.S. federal economic or energy policies."

None of the 41 surveyed disagreed.

"Do you believe that they are something a president can control? Many Americans believe that the answer is yes," Thaler wrote in The New York Times. "But any respectable economist will tell you that the answer is no."

Romney's snapshot glance at particular dates disregards the context of gas prices and their increasing volatility throughout the past decade.

When President George W. Bush took office, gas prices averaged $1.45 per gallon. Throughout his eight years in office, the national average to $4.12 per gallon by the summer of 2008, according to GasBuddy.com statistics.

Over Bush's final six months in office, the average plunged on weakening demand and global recession to a low of $1.61 in late December 2008. Under Obama, prices rose to the same mid-$3 level they had seen under Bush, although the national average did not rise above the $4 mark again.

Even though most experts say the president, aside from manipulating the country's Strategic Petroleum Reserve normally saved for national defense, has little control over gas prices, voters still look to the candidates to provide leadership on the issue.

Most prefer Obama's energy policy to Romney's according to a poll conducted by the University of Texas. Overall, 37 percent of respondents felt Obama's energy policy was best for the country while 28 percent favored Romney. Thirty-five percent were unsure whose policies they favored.

"While job creation and the economy continue to top the list of concerns, 2 out of 3 consumers say energy issues are important to them," said Sheril Kirshenbaum, director of the University of Texas energy poll. "Support for increased production of domestic energy supplies remains strong, and we're also seeing a lot of interest in the promotion of alternative forms of energy and energy-saving technologies that crosses party lines."

According to the U.S. Energy Information Administration, the U.S. has increased its production of oil and petroleum 20 percent since 2008. Even with that boost, the domestic production only accounted for 53 percent of the nation's oil and gas consumption.

In the University of Texas poll, respondents favored both candidates who would expand domestic development – and pursue renewable technologies. Sixty-two percent of the 2,092 respondents said they would be more likely to vote for a candidate who would increase funding for new energy technologies.

Consumers supported an increase in renewable energy, with 58 percent saying they would be likely to vote for a candidate who supports financial incentives for companies. Forty percent say they support decreasing the use of coal – 46 percent of Democrats and 30 percent of Republicans.