As State Archivist Guy Rocha said recently, the road to the White House now goes through Nevada because Saturday's statewide caucuses will help to clarify presidential nomination races in both major parties. As I write, it appears that Hillary Clinton and Barack Obama will battle it out for the Democratic nomination while John McCain and Mitt Romney are the top Republican contenders.It's new to everyone in Nevada. The state has been a presidential battleground in general elections in the past, but for the first time the caucuses are front and center in the Democratic presidential selection process.That's not the way things looked just one month ago, when Sen. Clinton was thought to be a shoo-in for the Democratic nomination and McCain was running well behind Romney and Rudy Giuliani, which only goes to show how quickly the situation can change in this front-loaded primary season. We'll know who the nominees will be soon after "Super Tuesday," Feb. 5, when more than 20 state primaries are scheduled.Clinton and Sen. Barack Obama have crisscrossed the state in recent days, appealing to constituencies that were nonexistent in the first two major battlegrounds. A third of Nevadans are black or Hispanic. It's the nation's fastest-growing state, rapidly urbanizing around Las Vegas, where voters are preoccupied by growth issues like school overcrowding (in Clark County a new school opens every month to relieve the pressure), the availability of drinking water and the credit crunch in this fast-rising housing market. The race is considered too close to call. Obama leads Clinton 32-30 in a Reno Gazette-Journal poll released Monday, the only one taken since the New Hampshire primary. John Edwards, who has focused on South Carolina but will attend Tuesday's MSNBC debate in Las Vegas, trailed with 27 percent. That represents a significant tightening; in early December polls showed Clinton with a double-digit lead. This is the first time Nevada's caucuses may have a real bearing on the broader nomination fight. Moved to the early part of the primary calendar largely by Senate Majority Leader Harry Reid, the caucuses will be held in about 1,750 precincts statewide. Democratic Party activists hope for a turnout of 45,000 voters, or 10 percent of the state's registered Democrats. The prior record was a mere 9,000 in March 2004, when it was held long after Massachusetts Sen. John Kerry had sewn up the nomination and was an affair so small that all of Clark County caucused on one high-school football field. Voters here are eager to show the rest of the country that their votes matter too. "This is our chance to show we're about more than showgirls and slot machines," says Marta Fuentes, 26, who met Hillary Clinton as she canvassed a working-class Hispanic neighborhood.