LAS VEGAS -- Good Friday morning. Politics Nation has a long day on the trail, and the sun hasn't even considered rising, so pardon the brief edition today. Check back throughout the day for frequent updates. Here's what Nevadans, South Carolinians and Washingtonians are watching today:

-- In Nevada, a new Las Vegas Review-Journal poll puts Clinton ahead by nine points, with Obama running second and Edwards a distant third. Add to that a Zogby poll for C-SPAN and Reuters and we have a new RCP Nevada Average, in which Clinton leads by a skinny 3.7 points. Those numbers may change, though. The Review-Journal offered a glowing review for Barack Obama while hitting Clinton and Edwards in their endorsement, which ran today.

-- Another unpredictable factor, writes Nevada political guru Jon Ralston: Turnout is completely unpredictable. In 2004, just 9,000 Nevadans came out to caucus. This year, Senate Majority Leader Harry Reid ambitiously predicted 100,000 would show up. Ralston, who knows everything there is to know about Nevada politics, "will go out on a limb," he writes, and predict that the number will be somewhere between the two. Great. But it's not just Ralston who's confused. Even top campaign strategists are worried. An unpredictable electorate is a dangerous electorate.

-- Turnout projections got something of a boost yesterday when a judge in Nevada ruled in favor of the state Democratic Party and against the Teachers' Union, allowing caucuses in certain Strip casinos to continue. The ruling is a huge win for Obama, whose supporters in the Culinary Workers' Union will likely dominate those caucuses, giving him a few extra percentage points that might prove crucial to a victory. Judge James Mahan's decision was also a win for both national parties; as two related rulings are scheduled to be handed down in days by the Supreme Court, Mahan ruled that it is the parties' right to pick their nominee in their way.

-- Just days ago the Democratic race was a love-fest on a debate stage. Now it's devolving again, largely thanks to a few surrogates. Sure, three candidates are fighting for votes, but Marc Ambinder hypothesizes that outside groups, including UNITE HERE and AFSCME, are involved to such a degree because the race is acting as a predictor of the future of the labor movement. The latest shot across the bow: "Hillary Clinton does not respect our people," begins a UNITE HERE Spanish-language ad running in Nevada. Talk about escalating the rhetoric.

-- Republicans, meanwhile, have hummed this tune before, and every four years, it seems, it causes someone problems. "If somebody came to Arkansas and told us what to do with our flag, we'd tell them what to do with the pole, that's what we'd do," Mike Huckabee told a cheering crowd in Columbia, South Carolina, where the Confederate flag was once proudly displayed on the State Capitol. The irony, as the New York Times points out: It was former South Carolina Governor David Beasley, Huckabee's most prominent Palmetto State supporter, who moved the flag during his term in office.

-- Each candidate's travel schedule in Nevada says something important: That there are really only three cities with airports large enough for a fly-around (with the occasional exception of Pahrump, an hour west of Las Vegas). Okay, that was a joke. But a candidate's travel schedule in South Carolina says a lot more about his strategy: McCain is taking his last day on the Palmetto State trail on the coast, while Thompson and Huckabee are fighting for votes Upstate. The coasts are where recent transplants from the Midwest or the Northeast come to retire, while Upstate is home to more evangelicals and traditional Southern conservatives. No matter the outcome tomorrow, McCain is unlikely to get many votes from Huckabee Country, and the people of Myrtle Beach south to Charleston will ensure Huckabee's numbers stay low near the water. If that changes, and one over-performs in the other's territory, the race is going to be a blowout.

-- Weather Report Of The Day: Republicans head to the polls in slightly warmer, but still chilly South Carolina tomorrow. Upstate the highs will only reach into the lower 40s, while it will be in the low to mid-50s along the coast. Rain is expected virtually everywhere, which could significantly drive down turnout. In Nevada, a recent cold snap is subsiding slowly, with high-40 degree weather in Reno, mid- to upper-50s in Las Vegas and colder, into the 30s, in the northern part of the state. Still, when you're caucusing at the Bellagio, who cares what it looks like outside?

-- Today On The Trail: Edwards has an event at his Las Vegas campaign headquarters before heading to an event with Teamsters in Oklahoma City. Clinton holds an economic roundtable in Las Vegas before taking a lap on the Elko to Reno to Henderson circuit for rallies. Obama's taking the same circuit, starting in Reno before heading to Elko and ending in Las Vegas.

-- On the GOP side, Huckabee meets voters in Bluffton before rallying in Aiken, Greenville, Spartanburg, Rock Hill and Columbia. John McCain spends his time in Florence before heading to Myrtle Beach, Hilton Head Island and Mount Pleasant. And Fred Thompson heads upstate with stops in Seneca, Pickens, Spartanburg and Greenville. Romney joins the Democrats in Nevada for rallies in Elko and Reno. And Rudy Giuliani holds a space policy roundtable in Cape Canaveral before rallying in Titusville.

-- Today, Politics Nation hits the trail with Edwards, Obama and the Clintons. Check back for frequent updates.