A substantial shift in the vote preference among independents has given John McCain a slim lead over Barack Obama after the Republican convention. Independents now break for McCain by 15 percentage points (46 percent to 31 percent) in a FOX News poll released Wednesday.

Last month, Obama had a one-point edge among independents (August 19-20, 2008).

Overall, McCain leads Obama by 45 percent to 42.

Raw Data: Click here to view the full results of the poll. (pdf)

Before the Democratic convention, Obama led by 42 percent to 39 percent (August 19-20, 2008).

Independents are twice as likely to say McCain is "very qualified" to be president: 50 percent think McCain is "very qualified" compared to 24 percent for Obama.

In addition, McCain has an 11-point edge among men, up from a slim one-point lead previously.

McCain also leads Obama among white voters (50 percent - 36 percent), voters 55 years and over (45 percent - 37 percent), white Evangelical Christians (61 percent - 25 percent) and gun owners (56 percent - 27 percent).

Obama bests McCain among women (45 percent - 41 percent), moderates (48 percent - 35 percent) and black voters (76 percent - 13 percent).

As has been the case for most of the campaign, McCain has more strength of support from his party: 88 percent of Republicans support him while 79 percent of Democrats support Obama.

In addition, the number of Republicans who say they are "very satisfied" with their choice of candidates this year has increased more than 20 points — from 12 percent in June to 34 percent now. Among Democrats, 44 percent are "very satisfied," up from 42 percent (June 17-18, 2008).

There is a big change in which candidate voters think will win. In July, nearly twice as many said they thought Obama would win (51 percent to 27 percent). Today, views are evenly divided: 41 percent believe Obama will win and 40 percent say McCain.

Undecided Voters In Their Gut Go McCain

About one in seven voters is still undecided about their vote for president, and these are the voters who will likely determine who occupies the White House. What do these undecided folks feel in their gut about the candidates? To try to get at that the poll asked: If you had to make the "toughest decision" of your life, who would you rather get advice from — Obama or McCain?

The results show undecided voters may be more apt to pull the lever for McCain. A 46 percent plurality of undecideds would rather get advice from McCain — that’s nearly four times as many as the 12 percent that pick Obama.

By a 30-point margin (52 percent - 22 percent) independent voters choose McCain on this measure. Most Obama voters — 74 percent — would go to him for advice, though some 11 percent would ask McCain. Fully 89 percent of McCain voters would go to him in this situation and 2 percent would go to Obama.

All in all, by 50 percent to 34 percent voters would pick McCain for advice on this tough decision.

Opinion Dynamics Corp. conducted the national telephone poll of 900 registered voters for FOX News from September 8 to September 9. The poll has a 3-point error margin. This is the first polling that included the running mates on the presidential tickets.

Overall, by a 10-point margin, voters say McCain's selection of Palin as his vice presidential running mate makes them more likely to vote for him for president. Same thing for Biden's pick, by a 10-point margin voters are more likely to vote for Obama.

In addition, by 50 percent to 40 percent, more think McCain made the "smarter choice" for his running mate. Nearly one of four (23 percent) Democrats think McCain made the smarter choice while 9 percent of Republicans think Obama did.

Qualifications and Trust on the Issues

Majorities think Obama (67 percent) and McCain (87 percent) are "very" or "somewhat" qualified to be president. More people think McCain is "very" qualified to be president than think the same of Obama. Setting aside how they would vote, almost half of Americans (49 percent) think McCain is "very" qualified, and 32 percent think Obama is.

Among their party faithful, 72 percent of Republicans think McCain is "very" qualified, compared to far fewer Democrats — 57 percent — say the same of Obama.

By an 18-point margin voters think the McCain-Palin ticket "has more experience combined" and by a slim 4 points "has better judgment combined" than the Obama-Biden ticket.

The Democrats come out on top by 7 points on which ticket "will bring the right change to Washington."

On handling specific issues, Obama is trusted more to handle health care (+ 14 points), the economy (+ 4 points) and energy independence (+ 2 points). Obama's advantage on each of these issues is down a few points from August.

McCain is trusted more to handle terrorism (+ 20 points) and Iraq (+ 13 points).

Who will not just talk about it, but actually get something done? About half of voters (49 percent) think Obama is a "talker" and 34 percent say he is a "doer." For McCain, 30 percent say he is a "talker" while a 54 percent majority says he is a "doer."

Maybe being seen as a "doer" is why 52 percent say McCain would be best at surviving alone on a deserted island — far outdistancing Obama (19 percent), Palin (16 percent) and Biden (4 percent).

Favorable Ratings

The candidates and their spouses are well-liked. A 60 percent majority views McCain favorably and 57 percent have a favorable opinion of Obama.

Palin is already as well known to voters as Biden is, even though he has been in the national spotlight much longer — having running for president twice previously (in 1988 and 2008). Palin has a slightly higher positive rating (54 percent) than Biden (51 percent).

Just over half (52 percent) see Michelle Obama favorably, and nearly half (48 percent) see Cindy McCain positively.

Finally, of the four candidates, almost half (48 percent) say McCain has the most compelling personal story — twice as many as say the same of Obama (24 percent). Some 10 percent say Palin and 4 percent Biden.