Clinton in spotlight at Democratic convention

DENVER (Reuters) - Hillary Clinton prepared for a highly anticipated turn in the spotlight at the Democratic convention on Tuesday, and in advance she asked supporters to help her put Barack Obama in the White House.

"I ask all of you who worked so hard for me, who knocked on doors and made those phone calls, who got in arguments from time to time ... to work as hard for Barack Obama as you did for me," Clinton told a luncheon crowd of about 2,500 who also heard from Obama's wife, Michelle.

"Let's work our hearts out to elect Barack Obama and Joe Biden our next president and vice president," she said at an event sponsored by Emily's List, a group that backs Democratic supporters of abortion rights.

Both camps predicted Clinton would make an enthusiastic pitch for Obama during her evening appearance and end a rift that has clouded the convention to nominate the first-term Illinois senator to face Republican John McCain in the November 4 election.

The second day of the convention focused on economic themes and began to lay out Obama's plans to aid lower- and middle-class voters suffering in a faltering U.S. economy, which polls show is the top issue in the final months of President George W. Bush's term.

But the continued drama around Clinton and the lingering anger of her supporters after their bruising nominating fight meant her speech would be watched closely for her level of enthusiasm and degree of sincerity.

"She will thank her supporters and lay out the case for why they need to support Barack Obama," Terry McAuliffe, Clinton's campaign chairman, told reporters outside the convention hall. "She does it all. It's a good speech."

Obama, 47, had tried to ease the lingering tension by giving Clinton, a New York senator, and her husband, former President Bill Clinton, major roles at the convention. Bill Clinton will address the Democrats on Wednesday.

Hillary Clinton visited the convention podium on Tuesday afternoon to scout out the arrangements. Asked if she was excited about the speech, she said: "You bet."

Some of Tuesday's speakers cranked up the criticism of McCain at the urging of Democrats who wanted a tougher approach to the Arizona senator. The first night focused on presenting a softer, more personal side of the candidate.

RECYCLING BUSH

"It's clear: the only thing green in John McCain's energy plan is the billions of dollars he's promising in tax cuts for oil companies. And the only thing he'll recycle is the same failed Bush approach to energy policy," said Pennsylvania Gov. Ed Rendell, a Clinton supporter.

Kansas Gov. Kathleen Sebelius, at one time considered a possible vice president for Obama, used a reference from the "Wizard of Oz" to bring up McCain's seven homes.

"I'm sure you remember a girl from Kansas who said there's no place like home. Well, in John McCain's version, there's no place like home. And home. And home. And home," she said.

Clinton, 60, is expected to free her delegates to back Obama on Wednesday. She will be formally nominated although a roll call vote by state could be cut short and Obama nominated by acclamation under a deal being negotiated by the two camps.

A daily Gallup tracking poll on Tuesday gave McCain a 2-point edge over Obama, 46 percent to 44 percent, within the margin of error but his first lead since Obama clinched the Democratic nomination in June.

Republicans say Obama is too inexperienced to take on the presidency and they sought to play up the Democratic divisions, releasing a new ad that repeated Hillary Clinton's criticism of Obama made during the primaries. It ended with an announcer saying "Hillary's right."

The convention's keynote speaker, filling the role that shot Obama to political fame at the Democratic convention in Boston in 2004, will be former Virginia Gov. Mark Warner.

Warner, favored to win his race for the U.S. Senate this year, plans to highlight economic initiatives in Virginia that helped him win over rural voters in normally Republican areas.

ABC News reported three men who were arrested on Sunday in the city of Aurora, east of Denver, had admitted to a plan to kill Obama using a rifle. Authorities had earlier played down the incident.

"We're absolutely confident there is no credible threat to the candidate, the Democratic National Convention or the people of Colorado," a statement from the U.S. attorney in Colorado said.

(Additional reporting by Jeff Mason, Rob Doherty, Karey Wutkowski and Andrea Hopkins; Editing by David Wiessler)