Obama buoyed in Iowa; urges supporters to vote

By Deborah Charles

SIOUX CITY, Iowa (Reuters) - Democratic presidential candidate Barack Obama was buoyed on Tuesday by some good news in an Iowa opinion poll but warned his backers they need to show up and vote this week if they want him to win.

"It looks like it might work," Obama told a cheering rally in this western Iowa city, two days before Iowans launch the state-by-state nominating contests that will pick Republican and Democratic nominees for the White House race.

"It looks like we just might do this thing -- to the surprise of many."

The first-term senator from Illinois, who would become the first black president if he wins the November 2008 general election, cautioned against complacency.

"The polls look good. But understand this. The polls are not enough. The only thing that counts is whether or not you show up for caucus," he told about 750 sign-waving supporters at a gathering earlier in the day in Des Moines.

"Make the phone calls and knock on the doors and grab your friends and grab your neighbors and say it is time for us to deliver on change," Obama said.

Obama, New York Sen. Hillary Clinton and former North Carolina Sen. John Edwards have been locked in a tight race in Iowa for the Democratic nomination in the past few months.

But a poll published on Tuesday in the Des Moines Register showed Obama had opened a gap and was leading with 32 percent of likely Democratic caucus-goers, compared to 25 percent for Clinton and 24 percent for Edwards.