State of the Union preview from the AP:

By JIM KUHNHENN and JULIE PACE
Associated Press

WASHINGTON (AP) -- Seeking to focus on nation-building at home, President Barack Obama will use his State of the Union address to call for more spending on infrastructure and manufacturing, while also announcing the withdrawal of 34,000 U.S. troops from Afghanistan within a year.

The highly-anticipated announcement on the next phase of the troop withdrawal will cut the size of the U.S. troop presence in Afghanistan in half by next February. The drawdown puts the U.S. on pace to formally finish the protracted war by the end of 2014.

A senior administration official confirmed the size of the troop drawdown on the condition of anonymity in order to discuss the announcement ahead of the president.

Read more.

According to excerpts released by the White House, President Obama will focus on the "unfinished task" of restoring America's middle class.

The president will say:

"It is our generation's task, then, to reignite the true engine of America's economic growth – a rising, thriving middle class.
"It is our unfinished task to restore the basic bargain that built this country – the idea that if you work hard and meet your responsibilities, you can get ahead, no matter where you come from, what you look like, or who you love.
"It is our unfinished task to make sure that this government works on behalf of the many, and not just the few; that it encourages free enterprise, rewards individual initiative, and opens the doors of opportunity to every child across this great nation of ours."

The Associated Press has already reported that one of President Obama's big announcements will be that 34,000 U.S. troops will be back home from Afghanistan within a year. "That's about half the U.S. forces currently serving there, and marks the next phase in the administration's plans to formally finish the war by the end of 2014," the AP reports.

In his response to President Obama, Sen. Marco Rubio of Florida will argue that a free enterprise system without Washington interference creates a stronger middle class.

"Presidents in both parties – from John F. Kennedy to Ronald Reagan – have known that our free enterprise economy is the source of our middle class prosperity," Rubio will say, according to excerpts released by his office. "But President Obama? He believes it's the cause of our problems."

White House Press Secretary Jay Carney said during a press briefing last week that Keenan had taken the lead for this speech and "will be getting a higher profile in the weeks to come." "These are speeches that the President takes very seriously," Carney said. "He's a writer himself, so he engages at a very deep level on the framing of a speech, on the writing of it and the editing of it and the shaping of it."

One of the strangest stories tonight is that Ted Nugent, the rock musician, will attend the State of the Union. According to The Washington Post, he will be Rep. Steve Sockman's guest.

Good evening and welcome to the official start of NPR.org’s live-chat coverage of President Obama’s 2013 State of the Union address. (Everything you’ve seen before now has been the prequel.)

Based on what the president has said in recent days, we expect him to spend much of his time tonight discussing his proposals for boosting the economy and creating jobs as he lays out a second-term agenda that includes steps to reduce the the national debt and deficits, immigration overhaul, gun control and climate change.

You'll also be seeing updates from NPR's Eyder Peralta who is live-blogging everything State of the Union tonight.

Tonight has turned out to be a big news night in a way we didn't expect. Not only do we have the president's State of the union but we have the situation with the alleged cop killer out in Great Bear Lake, California.

It obviously will be a challenge for news organizations to cover both the president's speech the major breaking crime story in Southern California.

Tmace, that's a great question. I'd be surprised, though, if much of this speech hits on Mali or Syria. We know he'll talk about continued troop withdrawals but we think much of the speech will focus on domestic matters.

@Not MittRomney: Rubio will give the Republican response about five minutes after the President leaves the chamber. Rand Paul is set to give the Tea Party response after Rubio is finished.