(CNN) - In what could be an ominous sign for Barack Obama just days before he is formally named the Democratic presidential nominee, a new CNN poll of polls out Tuesday shows the Illinois senator's lead over John McCain has been cut in half in recent days.
According to CNN's average of several recent national surveys, Obama's lead is now a slim 3 points over the Arizona senator, 46-43 percent - half of his advantage in a CNN poll of polls one week ago, and down from a high of 8 points in mid-July.
The latest poll results come amid increased attacks from McCain on Obama's readiness to be commander-in-chief and the re-emergence of national security worries among voters in the wake of the Georgia crisis.
"Over the last week, we've seen Sen. Obama's lead in the poll of polls cut in half," noted CNN Senior Political Researcher Alan Silverleib. "This change was likely driven by a renewed focus on foreign policy after Russia's invasion of Georgia, as well as by Sen. McCain's willingness to launch more aggressive attacks against Obama on issues such as off-shore drilling."
A Los Angeles Times/Bloomberg poll out Tuesday evening was the latest national survey to indicate Obama's lead is dwindling, putting the Illinois senator ahead of McCain by only 2 points, well within the poll's margin of error. The CNN Poll of polls also includes new surveys from Quinnipiac and Gallup.
But the recent downturn in the polls for Obama may not last - the Democratic White House hopeful is headed for a week of what is likely to be overwhelmingly postive coverage as he names his running mate and officially accepts his party's presidential nomination.
"The big question now is whether Obama can successfully regain control of the campaign agenda as we head into the Democratic convention," Silverleib also said.