The Washington Post reported Sunday the junior senator from Illinois is preparing for a possible race against Republican John McCain, the Arizona senator and Vietnam War hero.
Obama's patriotic talk early in the campaign was an attempt to guard against a potential political vulnerability down the campaign trail, said Tad Devine, a Democratic strategist unaffiliated in the primary.
"In successful campaigns, you recognize your potential liabilities and figure out how to turn them into strengths," he said.
Obama has warned against using the Sept. 11, 2001, terror attacks to "scare up votes instead of as a way to bring the country together," and has condemned the "politics of fear" while demanding an end to the "mind-set that got us into war" in Iraq.
"He has a willingness to confront a theme that has traditionally been a real liability for Democrats," said Jim Jordan, who ran part of John Kerry's 2004 Democratic presidential campaign.
"He talks about love of country in a more convincing and natural way than most Democrats do, than we've seen in a long time."