NASHVILLE, Tennessee (CNN) -- A national poll of debate watchers suggests that Sen. Barack Obama won the second presidential debate.

Fifty-four percent of those questioned in a CNN/Opinion Research Corp. survey conducted after the debate ended said that Obama did the best job in the debate, with 30 percent saying Sen. John McCain performed better.

According to the poll, 64 percent had a favorable opinion of Obama after the debate, up 4 points from before the event. Fifty-one percent of those polled had a favorable opinion of McCain after the debate, unchanged from before its start.

A majority said Obama seemed to be the stronger leader during the debate, 54 percent to 43 percent, and by a more than 2-to-1 ratio -- 65 percent to 28 percent -- viewers thought Obama was more likable during the debate.

CNN polling director Keating Holland said Obama made some gains on the leadership issue even before the debate.

"McCain's advantage on leadership shrunk from 19 points in September to just 5 points this weekend," Holland said. "If Obama can use this debate to convince Americans that he is a stronger leader than McCain, he may be difficult to defeat." Watch entire debate: 1 » | 2 » | 3 »

A majority of debate watchers polled thought Obama was more intelligent, by a 57 percent to 25 percent margin over McCain. Debate watchers also thought Obama more clearly expressed his views by a 2-to-1 ratio, 60 percent to 30 percent.

Debate watchers questioned thought McCain, rather than Obama, spent more time attacking his opponent, with 63 percent saying McCain went more on the attack, as opposed to just 17 percent saying Obama.

Half of those polled said Obama answered questions more directly, 13 points ahead of McCain, and by a 14-point margin, debate watchers thought Obama seemed to care more about the problems of audience members who asked questions. Read entire transcript of debate

McCain did come out on top in one category that neither candidate wants to win. By a 16-point margin, debate watchers thought the Arizona senator seemed more like a typical politician during the debate.

"For McCain, the key finding may be that his favorable rating did not change at all," Holland said. "It's unclear whether Obama will gain any momentum from Tuesday night's debate, but it looks like McCain will not do so. For a candidate who has consistently been a few points behind in national polls, that's not a good sign."

The poll suggests that independent voters thought Obama won the debate. Fifty-four percent of those identifying themselves as independents said the Illinois senator performed best, with 28 percent saying that McCain did the better job. iReport.com: Who do you think won the debate

Among Democrats, 85 percent said Obama won, with just 5 percent saying McCain did better. Among Republicans, 64 percent said McCain won, with 16 percent saying Obama did better.

Most debate watchers thought Obama won the first presidential debate September 26. According to a CNN/Opinion Research Corp. poll taken after that debate, 51 percent of those polled thought Obama did the better job, while 38 percent said John McCain did better.

The CNN/Opinion Research Corp. poll was conducted by telephone with 675 adult Americans who watched the debate. All interviews were taken after the end of the debate. Full coverage of the debates

The audience for Tuesday's debate was 38 percent Democratic and 31 percent Republican, which is very close to the partisan breakdown among all Americans nationwide. The survey's sampling error is plus or minus 4 percentage points.

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