Undecided voters have dwindled in the closing days of the United States presidential election, which may blow the hope of a final comeback of Republican presidential nominee John McCain, a new survey shows.

The ABC News poll coming out Sunday said that nearly a quarter of likely voters report that they have already cast their ballots; while among the rest, 93 percent say their minds are definitely made up.

That underscores the peril for McCain, trailing Democratic nominee Barack Obama in vote preference with relatively few minds left to change.

The shrinking size of movable voters marks the final shift from persuasion to turnout -- an effort, by each side, to get its voters to vote.

On that question the game's been changed by early voting.

Twenty-four percent of likely voters in this tracking poll say that they've already voted, compared with a total early or absentee vote of about 22 percent in 2004 and 15 percent in 2000.

There is apparently more to come: an additional 14 percent say they still plan to vote early or absentee, though their time is running short.

Among the remaining, the pickings are slim.

Excluding those who have already voted, just 7 percent of likely voters say they're either entirely undecided or may yet change their choice, and half say in fact it's pretty unlikely they will change their minds.

The portion of undecided voters have shrunk from 30 percent at the start of the campaign in May to 26 percent before the conventions, 19 percent after and on to its single-digit level now.

Obama, meanwhile, continues a steady lead in vote preference, built in no small part on the preference of those early voters.

Overall, among all likely voters, Obama continues to lead McCain by 53-44 percent, while early voters favor Obama by a broader 59-40 percent.

In terms of party affiliation, the gap between Democrats and Republicans among likely voters has reached 10 points, matching its average among all Americans in ABC polls this year.

It is up from an equal Democratic-Republican split in partisan allegiance in 2003.

(Xinhua News Agency November 3, 2008)