Palin's popularity rises

Voters can't cast ballots separately for vice president in November, of course.

But if they could, a new national poll released this morning suggests that Republican Sarah Palin would beat Democrat Joe Biden -- yet another sign of the popularity of John McCain's high-risk veep choice.

While the same CNN/Opinion Research Corp. survey found Barack Obama and McCain statistically tied -- Obama with 49 percent, McCain with 48 percent -- Palin leads Democrat Joe Biden 53 percent to 44 percent.

The first-term Alaska governor's favorability rating is also higher than the veteran Delaware senator's -- Palin's is 57 percent favorable, 27 percent unfavorable, while Biden's is 51 percent favorable, 28 percent unfavorable.

Palin's rating has improved since the Republican convention last week; it was 38 percent favorable, 21 percent unfavorable just after she was introduced.

And 58 percent of registered voters rate McCain's choice of Palin as excellent or pretty good, up from 52 percent a week earlier.

The poll was conducted Friday through Sunday and has an overall margin of error of plus or minus 3 percentage points.