As Illinois Sen. Barack Obama prepared for what could be the most important day of his life – his potential election as the nation’s first African-American president of the United States – the moment was marred by the death of his beloved grandmother.

“Toot,” as he called her, helped to raise him, and she succumbed to cancer at the age of 86 on the eve of the historic election in which Obama – whose campaign raised record-breaking funds and built new political coalitions – holds a significant lead in the polls nationally.

Madelyn Dunham, who had been described by Obama in numerous speeches and interviews as a surrogate mother, a pioneering female executive and a proud World War II wife who worked on a bomber assembly line.

“She was the cornerstone of our family,” Obama and his sister, Maya Soetoro-Ng, said in a statement announcing their grandmother’s death. “She was the person who encouraged and allowed us to take chances.”

The candidate recently took time off from his campaign to visit her in Hawaii as it became apparent that death was near. Obama spent yesterday campaigning in Florida, North Carolina and Virginia, states that have not supported a Democratic presidential nominee in years. He posed for a group photo with his traveling staff in front of the gleaming white campaign plane emblazoned with the slogan that has carried him through his 632-day candidacy: “Change We Can Believe In.”

“This is our last rally,” Obama told a sea of supporters in Manassas, Va., Monday night. “After decades of broken politics in Washington, eight years of failed policies from George Bush and 21 months of a campaign, we are less than one day away from bringing about change in America.”

National polls show voters continue to favor Obama in this historic presidential election.According to a Gallup Poll, Obama has an eight-point lead among likely voters over McCain, who ended his day campaigning in his home state of Arizona.

If voting trends follow poll patterns on Nov. 4, Obama will become the first African-American president of the United States. Although Obama has taken a firm lead in the polls, battleground states could determine it all.

Virginia has voted for a Republican for president since 1964. But large surges in Democratic registration could prove to be an advantage for Obama in these swing states.

“It’s one of the most important states,” Rashad Roberts of Woodbridge, Va., said. “Virginia can tip the race either way.” Since January, Democrats have registered more than 400,000 new voters. Early voting records show that Democrats outnumber Republicans in Florida, North Carolina, Iowa, Colorado, and Nevada.