SCENARIOS: How candidates are faring in key states

(Reuters) - The U.S. presidential election on November 4 hinges on a handful of battleground states where opinion polls show Democrat Barack Obama making significant gains against his Republican rival, U.S. Sen. John McCain of Arizona.

Obama leads in all of 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.

A candidate needs 270 electoral votes to win the Electoral College and capture the White House.

The president is determined not by the most votes nationally but 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 details about each state contest.

* 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. One weekend poll showed Obama ahead by 10 points, holding a lead that opened as the financial crisis moved to center stage in the campaign.

* 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 swing state with a heavy concentration of older voters who could favor McCain. It also has many Jewish voters who are normally Democratic but have been wary of Obama. A poll on Saturday gave Obama a 5-point edge, the latest in a string of surveys that have shown him leading in a state that McCain must win to take the presidency.

* 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 native Illinois and he has poured resources into his Indiana campaign after finishing a strong second to Sen. Hillary Clinton in the May Democratic primary. Republicans have begun to advertise there but polls have shown Obama closing the gap. The two most recent polls gave McCain a lead of between 5 and 7 points.  Continued...