Prop. 8 trailed in The Field Poll’s initial measurement in July by nine points (51% No to 42% Yes) taken shortly after it qualified for the ballot.

The No-side advantage increased to fourteen points (52% to 38%) in September, when voters were asked to react to its original ballot description, which referred to the measure as the “Limit on Marriage” initiative. However, following the state Supreme Court’s ruling that the state’s existing same-sex marriage ban was unconstitutional, thereby making it legal for same-sex couples to marry in California, state Attorney General Jerry Brown changed Prop. 8’s official ballot title to the “Eliminates Right of Same-Sex Couples to Marry” initiative. When voters were read this amended description in September, the No-side lead grew to seventeen points (55% No vs. 38% Yes).

Now, after more than a month of intensive campaigning on both sides, the initiative trails by just five points, 49% No vs. 44% Yes, with 7% undecided. Yes-side support has increased six points, and those opposed declining six points over the past month.

Gallup polling in October finds little evidence of a surge in young voter turnout beyond what it was in 2004. While young voter registration may be up slightly over 2004, the reported level of interest in the election and intention to vote among those under 30 are no higher than they were that year.

What's more, 18- to 29-year-olds continue to lag behind Americans aged 30 and older on these important turnout indicators.

As a result, 18- to 29-year-olds now constitute 12% of Gallup's traditional likely voter sample, basically the same as the estimate in the final 2004 pre-election poll (13%). Gallup's expanded likely voter model, which defines likely voters differently (on the basis of current voting intentions only), estimates a slightly higher proportion of young voters in the electorate (14%). However, even if the share of the youth vote were adjusted upward, doing so has little or no impact on the overall Obama-McCain horse-race numbers using either likely voter model.

It is possible that the 18- to 29-year-old share of the likely voter electorate will grow in the final days of the election. Although interest in the election and voting intentions usually increase as Election Day grows nearer, Gallup did not observe much of an increase from mid- to late October 2004, because interest was already at high levels (as it is this year).

A second possibility for heightened youth turnout would be voter mobilization efforts. Such efforts can convince people with little motivation or interest in the campaign to actually vote on Election Day. Gallup has been measuring voter contact in its daily tracking poll this week in an effort to gain a better understanding of this important component of the "ground game" in the final days of the campaign.

As of Oct. 27-29 polling, 39% of 18- to 29-year-olds had been contacted by either the Obama or McCain campaigns. That is the same contact rate seen among 30- to 49-year-olds, but is well below that of Americans 50 and older. So thus far, in a general sense, mobilization efforts have not reached the young voters to the same extent that they have older voters.

While Gallup data do suggest that voter turnout among young people will be high this year (as it was in 2004) compared to historical turnout rates, the data do not suggest that it will be appreciably higher than in 2004. Even if more young voters are registered this year, they do not appear to be any more interested in the campaign or in voting in the election than they were in 2004.

Unless turnout rates among older age groups drop substantially from what they were in 2004, young voters should represent about the same share of the electorate as in the last presidential election. And Gallup's data suggest interest in the campaign and voting are the same or higher among older voters compared to what they were in 2004.