US election: Guide to the battle

The state of the economy was a major concern for most US voters even before the financial crisis hit Wall Street.

Now it has become the key factor determining their choice of candidate. This has benefitted Mr Obama, who is generally seen as better prepared to handle the situation.

The Republicans have warned that Mr Obama would be a "tax and spend" Democrat who would limit wealth creation.

The other big domestic concern for voters is the rising cost and lack of healthcare coverage. This has also benefitted the Democrats, although both candidates have expensive plans to reduce the cost of health insurance and extend coverage to the uninsured.

Meanwhile, the war in Iraq has faded away as a vote-determining factor - partly because of the success of the surge.

Mr McCain's advantage of foreign policy experience has been countered by Mr Obama, who has attacked the failure of the Republican administration to catch Osama Bin Laden.

Two other issues have dropped way down the agenda:

• Immigration has not been the subject of a major debate, as both presidential contenders have moderate views on the subject.

• Abortion and other social issues, such as gun control, have faded as election issues, because the Democrats have appeared less ideological than in earlier years.