[cnn-photo-caption image=http://i.cdn.turner.com/cnn/2008/images/06/30/art.obamaflag.gi.jpg caption="Obama has been looking to emphasize national service."]
(CNN) - Sen. Barack Obama on Wednesday unveiled a plan to create volunteer and service opportunities to help tackle some of the nation's most pressing issues, part of his weeklong focus on patriotism and national service.
"This won't be a call issued in one speech or one program - I want this to be a central cause of my presidency," Obama said in a speech at the University of Colorado in Colorado Springs.
"We will ask Americans to serve. We will create new opportunities for Americans to serve. And we will direct that service to our most pressing national challenges."
He added, "When you choose to serve - whether it's your nation, your community or simply your neighborhood - you are connected to that fundamental American ideal that we want life, liberty and the pursuit of happiness not just for ourselves, but for all Americans. That's why it's called the American dream."
Obama highlighted his time as a community organizer on Chicago's South Side and his stint heading Project Vote, a group that helped register 150,000 new African-American voters in the Illinois city, according to his campaign.
"I wasn't just helping other people. Through service, I found a community that embraced me; citizenship that was meaningful; the direction I'd been seeking. Through service, I discovered how my own improbable story fit into the larger story of America," he said.
The presumptive Democratic presidential nominee also touched on the "spirit" of service witnessed after the September 11, 2001, attacks and take aim at the Bush administration's failure to capitalize on this opportunity to call Americans to service.