LAS VEGAS  To deliver messages on the need for energy savings, Democrat Barack Obama and Republican John McCain this week are choosing the same unlikely backdrop — this 24/7 playground of air-conditioned casinos and neon-lit desert skies.

On Tuesday, Obama promised "a very different vision of what this country can and should achieve on energy." McCain arrives Wednesday to discuss his plans for renewable fuels at the University of Nevada-Las Vegas campus.

Why preach conservation in a city that celebrates excess? The decision may have had less to do with the candidates' messages than with their electoral strategies.

"It's a sign that the electoral map is very competitive," said Brian Krolicki, Nevada's lieutenant governor and a McCain supporter. "Every state counts."

Obama's visit is part of a strategy to score upset victories in the traditionally Republican but independent-minded region that lies between California and the Rocky Mountains. "The winning-the-West strategy," as Danny Thompson, head of the Nevada AFL-CIO, called it, could help Obama win overall even if he falls short in some of the industrial battleground states. In Pennsylvania, for example, Hillary Rodham Clinton beat Obama decisively during the primaries.

Clinton won, but much more narrowly, in Nevada and New Mexico — both of which Obama visited this week. Together with Colorado, the states represent a combined 19 electoral votes, just one fewer than Ohio, the state that decided the 2004 presidential election.

President Bush won all three Western states that year, but by close margins. Since then, Democrats have scored gains in gubernatorial, congressional and state legislative races. "These states are becoming more and more Democratic," says Joel Kotkin, a California-based scholar who studies the nation's demographic trends.

On paper, this should be McCain country. The Republican has represented neighboring Arizona for more than 25 years in Congress and, as Obama himself acknowledged Monday, "can legitimately tout moments of independence from his party in the past."

In a region heavily populated by Hispanics and people drawn to the West's outdoor lifestyle, it doesn't hurt that two of those moments came over an immigration bill — McCain irked conservatives by co-sponsoring legislation that would have given undocumented immigrants a chance to stay — and legislation to combat global warming.

Obama commended McCain here Tuesday for "speaking out on climate change" and for his efforts to promote electric cars. But Obama criticized him for opposing a 2005 energy bill that included tax credits for renewable fuels such as solar and wind power, and for backing plans for more oil drilling off the nation's coasts.

McCain "is putting the country first with the best ideas from both parties," Tucker Bounds, a spokesman for the Republican candidate, replied in a statement.

Obama's energy plan includes a tax break for middle-income households to help offset the rise in gas prices. Long term, he said, the country should invest more in promoting conservation and developing alternative energy sources. Obama said he's against expanded offshore drilling and would consider more nuclear power only if better means are developed to deal with the environmental hazard posed by spent fuel.

That's a popular stance in Nevada, where local politicians have been battling to block a proposed national nuclear waste repository in Yucca Mountain.

McCain's local appeal may be diminished by "noise" over the economy and the war in Iraq, said Christine Sierra, a professor of political science at the University of New Mexico.

"Under better circumstances, McCain, as a senator from Arizona, would have a real advantage," she said.

Obama has his own challenges. His New Mexico visit was designed to attract women who backed Clinton. At a small roundtable, reminiscent of the ones Clinton made hallmarks of her "listening tours," he was introduced by the state's lieutenant governor, Diane Denish, "an early and enthusiastic Hillary Clinton supporter," by her own description.

"I want my daughters to grow up in an America where they have the exact same opportunities as the boys," Obama said.

Obama finishes up a two-week campaign tour focused on the economy in Pittsburgh on Thursday. On Friday, he heads to New Hampshire for his first joint campaign appearance with Clinton.