SCENARIOS- How Obama and McCain are faring in key states

(Reuters) - Next week's U.S. presidential election will be decided in a handful of battleground states where opinion polls show Democrat Barack Obama and Republican rival John McCain in sometimes tight races.

Obama, who leads in virtually every national opinion poll, is also ahead in all the states won by Democrat John Kerry in 2004 as well as in several states won by Republican President George W. Bush, recent polls show.

But some races appear to be tightening or even tied. The victor will need 270 electoral votes to win the Electoral College and capture the White House in the November 4 election.

The president is determined not by the most votes nationally but by a majority of the Electoral College, which has 538 members allotted to all 50 states and the District of Columbia in proportion to their representation in Congress.

Each state, except Maine and Nebraska, awards its votes to the candidate who gets the most votes in the state. Maine and Nebraska split them by congressional district.

Here are some battleground states with their electoral vote totals, 2004 results and recent details about the contests in each state.

* Colorado -- Nine electoral votes. Bush beat Kerry 52 percent to 47 percent in the state in 2004, but since then, Democrats have won the state Legislature and governor's office. A poll on Monday showed Obama up by 4 points, while surveys last week gave him wider leads.

* Florida -- 27 electoral votes. Bush beat Kerry 52 percent to 47 percent in a state known for the disputed result that decided the 2000 election. Florida is a classic swing state with many older voters who could favour McCain along with Jewish voters who are normally Democratic but have been wary of Obama. One poll on Monday gave Obama a 4-point lead while another said the race was tied.

* Indiana -- 11 electoral votes. Bush beat Kerry by 20 points in 2004 in a state that last voted for a Democrat in 1964. But it borders Obama's home state of Illinois and he has poured resources into his Indiana campaign after finishing a strong second to Sen. Hillary Clinton in the May Democratic primary. A Monday poll showed McCain ahead by 6 points while a survey last week gave Obama a 10-point edge in the state.