Charlie Neibergall/AP Photo

When President Obama took the stage Thursday night to accept his party's nomination in Charlotte, N.C., he made a pitch for a second term in a neck-and-neck race. It's his third speech to Democratic conventions since he appeared on the national scene in 2004. Since then he has gone from upstart state senator to the nominee of "hope and change" to embattled president in a struggling economy.

He noted the timeline in his speech. Here's a look at the three Obamas: '04, '08 and '12.

2012:

"You know, I recognize that times have changed since I first spoke to this convention. The times have changed - and so have I. I'm no longer just a candidate. I'm the President," he said Thursday night.

"If the critics are right that I've made all my decisions based on polls, then I must not be very good at reading them. And while I'm very proud of what we've achieved together, I'm far more mindful of my own failings, knowing exactly what Lincoln meant when he said, 'I have been driven to my knees many times by the overwhelming conviction that I had no place else to go," he said.

"America, I never said this journey would be easy, and I won't promise that now. Yes, our path is harder - but it leads to a better place. Yes, our road is longer - but we will travel it together. We don't turn back. We leave no one behind. We pull each other up. We draw strength fro our victories, and we learn from our mistakes, but we keep our eyes fixed on that distant horizon, knowing that Providence is with us, and that we are surely blessed to be citizens of the greatest nation on Earth."

2008:

Four years ago, then-Sen. Obama took the convention stage for what was arguably one his most memorable speeches, marching out into a jam-packed Invesco Field in Denver to accept the Democratic Party's nomination. It was the first open-air stadium acceptance speech at a convention since John F. Kennedy's in 1960, and as more than 84,000 attendees looked on, Obama energized them with his now-famous message of change:

"For 18 long months, you have stood up, one by one, and said 'enough' to the politics of the past. You understand that in this election, the greatest risk we can take is to try the same old politics with the same old players and expect a different result. You have shown what history teaches us : that at defining moments like this one, the change we need doesn't come from Washington. Change comes to Washington," he said.

"Change happens because the American people demand it - because they rise up and insist on new ideas and new leadership, a new politics for a new time. America, this is one of those moments. I believe that as hard as it will be, the change we need is coming."

2004:

Obama's first appearance on the stage of the Democratic National Convention came in Boston, when Sen. John Kerry was the nominee, and Obama was a first-time U.S. Senate candidate largely unknown outside his home state of Illinois. He delivered the keynote address on the second night of the convention, spellbinding attendees with a message of unity and spurring speculation that he would one day run for president himself:

"John Kerry believes in America. And he knows that it's not enough for just some of us to prosper. For alongside our famous individualism, there's another ingredient in the American saga: A belief that we're all connected as one people … It's what allows us to pursue our individual dreams, and yet still come together as one American family. E pluribus unum: Out of many, one," he said.

"Tonight, there is not a liberal America, and a conservative America. There is the United States of America. There is not a black America and a white America and Latino America and Asian America. There's the United States of America … We are one people - all of us pledging allegiance to the stars and stripes. All of us defending the United States of America. In the end, in the end - in the end, that's what this election is about. Do we participate in the politics of cynicism, or do we participate in the politics of hope?"