In Clark County, 347,000 votes were on the books through the end of voting Thursday night, a turnout of 43 percent of the county's active registered voters. By mid-afternoon, it was up to 373,000, and Lomax predicted the number would reach 390,000, or 48 percent, by day's end.

Total countywide turnout in the 2004 election was 80 percent, with half of that coming during early voting. County Registrar of Voters Larry Lomax said considering the huge amount of early votes, it was likely that the total turnout rate would surpass that of four years ago, and that the proportion of votes cast early would rise to more than 50 percent.

Lomax said some voting sites had long lines Friday, but they moved briskly, and the longest waits were no more than an hour. Voters at some of the busiest sites confirmed long but fast-moving lines.

Throughout the early voting period, more Democrats have been showing up to vote than Republicans in the urban counties of Clark and Washoe, the only counties that report the party registration of early voters. Together, Clark and Washoe contain 87 percent of the state's voters.

Through Thursday, 52 percent of the voters in those two counties were registered Democrats, while just 31 percent were Republicans. The remainder were nonpartisans or members of minor parties.

Those statistics tell what party the voters belong to but not necessarily who is winning the election, of course. No election results are revealed until after the polls close on Election Day, which is Tuesday.

A Las Vegas consultant who has been conducting automated telephone "exit polls" finds that Democrats are ahead among early voters in key races. These results are presented with the caveat that they don't necessarily reflect those who have yet to vote.

Steve Nathan's firm Dialing Nationwide Automatically, or DNA, had surveyed 15,128 voters statewide by calling every person who had voted through Wednesday, according to state voting files. The responses were weighted to reflect the electorate.

The results showed Democratic nominee Barack Obama getting 53 percent of the vote to Republican nominee John McCain's 44 percent, with 3 percent choosing other candidates or "none of the above."

In the 2nd Congressional District, Democrat Jill Derby was receiving 53 percent of the early vote, while the Republican incumbent she is challenging, Rep. Dean Heller, trailed with 47 percent.

Nathan said the rural counties, which are heavily Republican, have lagged in reporting voter information, so they may be underrepresented in those tallies, which in turn may be slightly understating the Republican candidates' support as a result.

In the 3rd Congressional District, which is entirely in Clark County, rural turnout is not a factor and the Democratic challenger, state Sen. Dina Titus, had a lead over Republican incumbent Jon Porter in DNA's polling, 56 percent to 43 percent.

Obama and Titus saw their leads widen as more people voted, while Derby's lead narrowed, possibly because of the rural vote, according to the polling.

Nathan said he expects heavy Election Day turnout from the rural counties, but the leads the Democratic candidates are building may be insurmountable for their Republican opponents nonetheless, given the high early voting turnout.

Polls will be open from 7 a.m. to 7 p.m. Tuesday, with the busiest times expected at the beginning and end of the day. Voters must cast ballots at their assigned precinct locations, which can be found on the sample ballots they should have received in the mail.

Registered voters also can look up their polling places online at the Election Department Web site, www.accessclarkcounty.com/depts/election.

Contact reporter Molly Ball at mball @reviewjournal.com or 702-387-2919.