Washington (CNN) -- Despite the bruising battle over their proposals to overhaul health care, congressional Democrats have maintained an advantage over their Republican counterparts on one key measure, according to a new national poll.

A CNN/Opinion Research Corp. survey released Wednesday indicates that a bare majority of Americans, 51 percent, believe that the Democrats' policies are good for the country, with 46 percent saying that those policies would take the U.S. in the wrong direction.

Fifty-three percent of people questioned in the poll said the GOP's polices would move the nation in the wrong direction, with 42 percent saying Republican policies are good for the country.

"The numbers for both parties are virtually unchanged since late August, just before President Barack Obama's health care speech to Congress opened the latest round of debate on this divisive issue," said Keating Holland, CNN's polling director.

Democrats will be defending their large majorities in Congress next year when all 435 House seats and more than a third of the Senate seats are up for grabs.

"This advantage on policy could be an important edge for the Democrats heading into the 2010 midterm elections," Holland added. "But independents will be the key to the midterms, and the numbers among independents spell bad news for both parties among that important group."

In an August survey, independent voters' views of GOP policies were evenly divided. But a majority of independents now say Republicans would move the country in the wrong direction. Nonetheless, the number of independents who dislike Democratic policies, now at 57 percent, is higher than the 52 percent who hold a negative view of Republican policies.

The survey suggests that Sen. Joe Lieberman is taking a hit in popularity due to his opposition to a major element in the health care bill. The Connecticut independent, who caucuses with the Democrats to give the party a 60-vote filibuster-proof majority in the Senate, threatened to undermine the bill unless compromises were made. Lieberman opposed the creation of a government-run public insurance option and the expansion of Medicare to individuals as young as 55.

Both of those proposals were dropped from the bill this month, enraging many liberals.

According to the poll, Lieberman's favorable rating has dropped 9 percentage points, from 40 percent to 31 percent, from early December. His unfavorable rating has risen 6 percentage points, from 28 percent to 34 percent.

"Lieberman's biggest decline -- a 14-point drop -- came among independents," Holland said. "Only Republicans continue to like Lieberman."

The survey also indicates that just one in five Americans trust the federal government always or most of the time, down 4 percentage points from a year ago.

The CNN/Opinion Research poll was conducted December 16 through Sunday, with 1,160 adult Americans questioned by telephone. The survey's overall sampling error is plus or minus 3 percentage points.

CNN deputy political director Paul Steinhauser contributed to this report.