Washington (CNN) -- Support for President Obama has dropped below 50 percent for the first time in a CNN poll despite high marks for his recently announced Afghanistan policy.
Forty-eight percent of Americans questioned in a CNN/Opinion Research Corp. national survey released Friday said they approve of the job Obama is doing as president -- a drop of 7 percentage points from a survey last month.
Fifty percent said they do not approve. The difference of 2 percentage points between approval and disapproval falls within the range of the poll's sampling error.
"The poll indicates that the biggest drop in approval comes from noncollege-educated white voters," said Keating Holland, CNN's polling director. "That's one indication among many that Obama's growing unpopularity may be more related to unemployment and the poor economy" than to factors such as his strategy for Afghanistan.
Six in 10 of those questioned said they favor Obama's move to send 30,000 more troops to that country. Two-thirds also support his plan to start removing U.S. forces from Afghanistan in 2011 -- although the poll indicates most Americans think that announcing such a date in advance was a bad idea, and they are skeptical about whether conditions then will allow the United States to meet that goal.
And support for Obama's policies does not translate into backing for the war; a majority still said they oppose U.S. action in that country.
"That may currently be a reflection on George W. Bush rather than Obama," Holland said. "Two-thirds say they blame the former president, not Obama, for the problems the U.S. currently faces in Afghanistan."
But the poll suggests the conflict eventually may become Obama's war, with 54 percent saying they will blame him for any problems the U.S. faces in Afghanistan in 2011.
The poll was conducted Wednesday and Thursday after the president spelled out his new Afghanistan policy in a prime-time address Tuesday night at the U.S. Military Academy at West Point, New York.
Several polls in late November indicated Obama's approval rating had dipped this low even before this week's speech. Weekly averages of national polls from mid-October through mid-November showed Obama's approval consistently at 52 percent or 53 percent.
"But in the week before Thanksgiving, his average approval rating slipped to 49 percent -- solid evidence that something was going on before Obama announced his Afghan policy," Holland said.
Obama's rating dropped 18 percentage points among noncollege whites, but 4 points among whites who attended college, a good indication the economy and other domestic issues may be hurting the president.
Obama also dropped 15 percentage points among whites under 50, but 4 points among older whites.
"That may partly be due to Afghanistan," Holland said, "but the young are also the group hardest hit when unemployment rises. The same is true for white women, whose approval of Obama dropped 12 points."
Obama is not the first president to drop below 50 percent in his first year in the White House. President Reagan's approval rating dipped to 49 percent in November 1981 and stayed below that mark for two years. President Clinton also dropped well below the 50 percent mark by May 1993, the fastest fall on record.
The CNN/Opinion Research poll was conducted by telephone, with 1,041 people questioned. The survey's overall sampling error is plus or minus 3 percentage points.
CNN deputy political director Paul Steinhauser contributed to this report.