The visit to Nevada, a swing state in the presidential election, is Obama's first since the primaries ended and he became the Democratic Party's presumptive nominee earlier this month.

State Democratic leaders held a news conference Monday to project an air of unity for the occasion, saying former supporters of Hillary Clinton, who won more precinct delegates than Obama in the state's Jan. 19 caucuses, are now behind Obama.

"On January 19, we worked against each other, but that was then," said Clark County Commissioner Rory Reid, Clinton's Nevada campaign chairman. "Today, we're standing united."

Reid was joined by state Sen. Steven Horsford of Las Vegas, an Obama campaign leader, and other Democrats, including Clinton supporters such as former Gov. Bob Miller and state Sen. Dina Titus, a candidate for Congress.

A parallel event was held in Reno featuring state Treasurer Kate Marshall, a Clinton supporter, and Assemblywoman Sheila Leslie of Reno, an early Obama backer.

Reid said those loyal to Clinton would follow the New York senator's directions in supporting Obama.

"When Senator Clinton endorsed Senator Obama, she said, 'Life is too short, time is too precious, the stakes are too high to dwell upon what might have been.' I believe that, and I am going to work my heart out for Barack Obama," Reid said.

The two campaigns, he said, had "independently built significant organizations that, when combined, I think are formidable."

Obama's Republican opponent, John McCain, is scheduled to appear in Southern Nevada this week.

McCain plans to give a speech on energy and national security at the University of Nevada, Las Vegas on Wednesday morning. Limited space is available for members of the public, according to the campaign. Doors open at 8:30 a.m. E-mail nevada@johnmccain.com to RSVP.

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