DENVER -- Colorado is in the political spotlight Wednesday as Barack Obama comes to town and former president Bill Clinton prepares for an evening visit.

Both Obama and Clinton campaigns want to fire up supporters ahead of Super Tuesday.

Sen. Barack Obama packed a large crowd at the Ritchie Center at the University of Denver for what his campaign calls a "Community Gathering For Change." But the event felt more like a rock concert than a rally for a presidential hopeful.

The mostly young crowd in the hockey arena held signs reading "Barack the Vote" and "Colorado for Obama." At one point, they did the wave.

Large crowds started gathering outside before dawn and by the time the rally started, more than 12,000 people were at the venue, according to a campaign official. The crowd was so large that those who couldn't fit into the Magness Arena were taken to two overflow rooms and still others were left standing in a nearby athletic field.

Former Denver Mayor and former federal Transportation Secretary Federico Pena told the crowd that he hopes those in attendance are ready to attend caucuses next week to have a say in choosing the next president. Later, he led the crowd in a chant, first in Spanish, then in English, saying "Yes We Can."

Caroline Kennedy, daughter of the late President John F. Kennedy, introduced Obama and explained why she's throwing her support behind him.

"Over the years, I've been deeply moved by the people who've told me they wish they could feel inspired and hopeful about America the way people did when my father was president," she said. "This longing is even more profound today. Fortunately, there is one candidate who offers that same sense of hope and inspiration. That candidate is Barack Obama."

Obama finally stepped onto the podium at 11:05 a.m., an hour after he was scheduled.

He first made note of John Edwards exiting the Democratic race for president. Edwards made it official shortly before Obama stepped on the stage.

"John has spent a lifetime trying to give a voice to the voiceless and hope to the struggling," Obama said. "He has consistently made us focus on who matters. The New Orleans child without a home. The West Virginia miner without a job. The families that live in that other America that is not seen or heard or talked about in Washington. His campaign may have ended, but his cause lives on."

Obama catered to the Denver crowd, saying the looked like a crowd that might gather at the Democratic National Convention in Denver this summer.

"You guys don't have the funny hats yet. We need to get you some funny hats," he said.

"Seven months from now, the Democratic Party will gather here in Denver to nominate our candidate for president of the United States of America," Obama said. "This city, built at the base of the Rocky Mountains, stands as a monument to a uniquely American belief to things unseen. Here in Denver, fur trappers, traders, gold rushers came in search of opportunity. They carved out a new America where nobody else saw what is possible ... The story of America leads west."

He then went on to talk about the decision that voters will have to make when they elect the next president.

"The choice before you is about what comes next because we need to do more than turn the page on the Bush-Cheney policies," Obama told the crowd.

He said the war "should never have been authorized and should never have been waged." Obama said he opposed the war from the start and would immediately begin removing our troops, if he's elected.

"I will end this war," he vowed and said he would close the prison camp at Guantanamo Bay if he is elected president.

"I am running for president because I believe we don't just need small change. We need fundamental change in America," he said. "If you put your trust in me, I will stand up at that convention and say, "Our divisions are behind us and our time for change has come.'"

"Colorado, our moment is now," he said.

Obama Says Clinton Presidency Would Be Step Back

Democratic Sen. Barack Obama said Wednesday a Hillary Rodham Clinton presidency would be a step back to the past, turning her husband's image of a bridge to the future against her.

"I know it is tempting -- after another presidency by a man named George Bush -- to simply turn back the clock, and to build a bridge back to the 20th century," the Illinois senator said in Denver.

"... It's not enough to say you'll be ready from Day One -- you have to be right from Day One," he added in unmistakable criticisms of Clinton, who often claims she's better prepared to govern, and her husband, who pledged during his own presidency to build a bridge to the 21st century.

Obama depicted Clinton as a calculating, poll-tested divisive figure who will only inspire greater partisan divisions as she sides with Republicans on issues like trade, the role of lobbyists in politics and national security. At the same time, he elevated McCain, fresh off victory in Florida's crucial primary, as the likely Republican nominee.

"Democrats will win in November and build a majority in Congress not by nominating a candidate who will unite the other party against us, but by choosing one who can unite this country around a movement for change," Obama said, speaking as rival John Edwards was pulling out of the race in New Orleans, leaving a Clinton-Obama fight for the Democratic nomination.

"It is time for new leadership that understands the way to win a debate with John McCain or any Republican who is nominated is not by nominating someone who agreed with him on voting for the war in Iraq or who agreed with him in voting to give George Bush the benefit of the doubt on Iran, who agrees with him in embracing the Bush-Cheney policy of not talking to leaders we don't like, who actually differed with him by arguing for exceptions for torture before changing positions when the politics of the moment changed," Obama said.

"We need to offer the American people a clear contrast on national security, and when I am the nominee of the Democratic Party, that is exactly what I will do," he said.

"It is about the past versus the future," he said. "And when I am the nominee, the Republicans won't be able to make this election about the past.

"If you choose change, you will have a nominee who doesn't just tell people what they want to hear," Obama told them. "Poll-tested positions, calculated answers might be how Washington confronts challenges, but it's not how you overcome those challenges; it's not how you inspire our nation to come together behind a common purpose, and it's not what America needs right now. You need a candidate who will tell you the truth."

Obama finished his Denver speech at 11:55 a.m. Several prominent Democrats in Colorado, including Mayor John Hickenlooper, Colorado Senate President Peter Groff, U.S. Rep. Ed Perlmutter and former Sen. Gary Hart, were at the rally.

Obama's challenge is to get his new fans to learn about and go to the caucus next Tuesday. In fact, Obama's campaign polled a lot of people at the rally, asking them if they knew where their caucus location was and how the process worked. They even handed out simple instructions about how to attend a caucus.

Clinton Camp Responds With Own Rally

Less than 12 hours later, former President Bill Clinton and his daughter Chelsea will attend an event called "Solutions for America" at the same venue. Clinton is campaigning for his wife, Hillary.

The Clinton campaign said Obama was abandoning his pledge to run a positive campaign.

"Senator Obama doesn't sound like he's ready to practice the new politics he so often talks about. In fact, Senator Obama's remarks suggest that his talk about bringing the country together is just that -- talk," said Clinton spokesman Phil Singer.

Other Clinton supporters said Obama's rhetoric -- was just that -- rhetoric.

"It's not enough to hope for change, it's about making change a reality," said former Denver Mayor Wellington Webb.

Colorado is a caucus state, one of 22 to hold nominating contests Tuesday, and is one of a handful of states where the Obama campaign is predicting victory. Clinton has the advantage in several others, while several are still up for grabs.

A recent Denver Post poll show Obama and Clinton running neck and neck among Colorado voters; 34 percent for Obama and 32 percent for Clinton.

Other Candidates To Swing Through

On Thursday, President George W. Bush will stop in Colorado for a fund-raising event for Rep. Senate candidate Bob Schaffer. The event will held at a private residence in Cherry Hills Village. Tickets cost $5,000 per couple.

Then on Friday, Gov. Mitt Romney and Ron Paul will both be swinging through the state. They are vying for the Republican nomination.

Paul will speak at a 6 p.m. rally at the Denver Convention Center.

It's not clear where and when Romney will speak.

Colorado participates in Super Tuesday on Feb. 5 with statewide Democratic and Republican caucuses. Twenty one other states also have primaries or caucuses that day.

Bush To Honor Former 7Everyday Hero

When the president arrives at Buckley Air Force Base Thursday, he will also honor a woman who has volunteered for seven years at a program that provides eye care for the homeless.

Bush will present the President's Volunteer Service Award to Stout Street Eye Clinic volunteer Cherie Yager, a former 7Everyday Hero.

Yager worked as an optician in the Denver area for 25 years before quitting and volunteering at the clinic. More than 4,000 people received treatment at the clinic last year.

Bush typically honors local volunteers on his trips around the country.