WASHINGTON (Reuters) - President Barack Obama sought to energize Democratic loyalists on Wednesday in a speech laying out themes of his coming 2012 re-election bid, saying he has met many of his promises "but we aren't finished."

He gave an early version of his 2012 stump speech to a crowd of Democratic backers at a Washington hotel. Obama has not yet launched his re-election campaign, but is expected to do so in the coming months.

Obama said he would like to recreate the magic of his 2008 campaign, which he said was "like lightning in a bottle," when a big turnout from his Democratic base and independent voters carried him to victory.

He cited improvements in the U.S. economy, the winding down of the Iraq war and efforts to push the United States into a greater use of clean energy as evidence that "we have made extraordinary progress over these last two years."

"When you look back at the track record of the work that we've done over the last two years, I think it's fair to say the promise that we made to the American people has been kept. But we aren't finished. We've got more work to do," Obama said.

Obama at this stage measures up well in public opinion polls against a host of potential Republican challengers who are expected to compete for their party's presidential nomination.

But he will need to bring back into his fold many of the independent voters who fled the Democrats in November's congressional elections and helped Republicans win control of the U.S. House of Representatives.

Obama also talked about some of the stresses of the job on him and his wife, Michelle.

"There are times where Michelle reminds me that I volunteered for this job, because she looks at me and I looked tired. But I'm telling you, I am having an extraordinary time, because there aren't many moments in our lives where we know that we're making a difference," he said.

And the constant cable television news chatter can be annoying, he said.

"I'm sure that some of you are like Michelle and at some point had to just stop watching cable TV because it was getting too frustrating," he said.

(Editing by Mohammad Zargham)

[Image via the White House Flickr account]