(CNN) – A new poll released Sunday indicates the presidential race between Mitt Romney and President Barack Obama is still tight in a dozen major battlegrounds.
According to the latest survey by USA Today/Gallup, the president has a small advantage over his Republican rival, 47% to 45%, in 12 key states. The two-point margin falls well within the poll's sampling error.
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Obama's edge over Romney represents the same two-point margin he held when the same poll was last conducted in May.
When zooming out to include voters from the other states, the gap expands to a four-point margin in favor of Obama, 48% to 44%.
However, political observers and both campaigns say the race will ultimately be decided by a select portion of swing states.
Gallup surveyed voters in Colorado, Florida, Iowa, New Hampshire, Ohio, Nevada and Virginia - all states that CNN rates as toss-ups on its Electoral Map.
The poll also included voters in Michigan, Wisconsin, Pennsylvania, and New Mexico - four states CNN considers leaning toward Obama - as well as voters in North Carolina, a state leaning toward Romney, according to a CNN analysis.
Also of note, the poll shows the barrage of attack ads on swing-state airwaves has caused a slight change in voters' minds.
One in 12 say the commercials have altered their opinion about Obama or Romney, with 76% of them now favoring the president compared to 16% who say they switched to Romney.
Both campaigns have taken out state-specific commercials in such states as Iowa, Virginia and Ohio.
For the USA TODAY survey, Gallup questioned 1,200 registered voters in the dozen swing states by telephone June 22-29, with a sampling error of plus or minus four percentage points. For non-swing states, 2,404 registered voters were interviewed during the same time period.
–CNN Senior Producer Kevin Bohn contributed to this report.