FACTBOX: New Hampshire in play in tight White House race

(Reuters) - While only four electoral votes are at stake in New Hampshire, the tightening race between Republican John McCain and Democrat Barack Obama for the 270 electoral votes needed to win the White House makes the Granite State and other swing states such as Virginia critical.

HOW CLOSE?

* Polls show the race in New Hampshire is close with Obama ahead slightly. An average of polls by the Web site RealClearPolitics shows Obama leading McCain by a narrow 48 percent to 44.7 percent. A CNN/Time/Opinion Research Corp survey of 899 voters taken September 7 through 9 showed Obama leading McCain 51 to 45 percent. Andrew Smith, director of the University of New Hampshire's Survey Center, expects the race to be won by just a few thousand votes.

WHO SUPPORTS WHOM?

* According to the University of New Hampshire's Survey Center, McCain runs strongest among Republicans, conservatives, older voters, voters with high school diplomas and voters living in more affluent regions along the Massachusetts border.

* Obama does best among Democrats, liberals, younger voters, those who do not attend church and residents of New Hampshire's seacoast.

RED STATE OR BLUE STATE?

* The state of 1.3 million people has long been a Republican stronghold, supporting GOP candidates in every presidential election from the mid-1960s until 1992. Today, it is neither red nor blue but a shade of purple. In 2000, Republicans and Democrats each made up about 38 percent of the electorate. Six years later, Democrats expanded to 43 percent and Republicans shrank to 31 percent, with both parties chasing independent votes. President George W. Bush won the state in 2000 by a narrow 7,000 votes. In 2004, Democrat John Kerry carried the state by just 9,000 votes.

WHERE WILL THE ELECTION BE FOUGHT?

* Smith, director of the University of New Hampshire's Survey Center, expects the race to boil down to blue-collar voters in Manchester, a former New England textile city of 107,200 people. "Whoever wins Manchester probably wins the election in the state," he said. Fergus Cullen, chairman of the state's Republican Party, said Hillsborough County, which includes Manchester, will be critical along with Rockingham County that borders Maine to the northeast and Massachusetts to the south.

WHAT ARE THE TOP ISSUES?

* Both candidates say the economy is crucial in New Hampshire, which has the nation's sixth-highest per capita income and lowest poverty rates. Obama's campaign stresses McCain's senate votes against increasing funding for a home heating assistance program, an issue of particular relevance to New England as winter approaches. McCain's campaign is stressing his image as a tax-cutter and crusader against wasteful spending -- which should resonate in a state that prohibits income and sales taxes.

(Reporting by Jason Szep; Editing by David Alexander and Eric Walsh)