The White House released a video on Tuesday promoting the legacy of U.S. President Barack Obama ahead of his last State of the Union address.

Obama will present an agenda for his final year in office and beyond, aiming to paint an optimistic vision of America despite worries about immigration, terrorism and economic inequality.

The speech to a joint session of Congress will be one of Obama's few remaining chances to capture and hold the attention of millions of Americans before he is eclipsed by his would-be successors competing to win November's presidential election.

Politics will loom over the address. He is expected to stick to themes which he hopes will define his legacy and steer clear of new legislative proposals that his fellow Democrats on the presidential campaign are laying out.

Scheduled for 9 p.m. (0200 GMT on Wednesday), Obama's speech will try to generate support for some of his favored issues such as a Pacific trade pact, tighter gun laws and closure of the Guantanamo Bay prison.

Aides said he would offer a more optimistic view of the United States' standing, compared with the dire assessments put forth by Republican presidential hopefuls.

In an interview aired on Tuesday, Obama took a swipe at Republican candidate Donald Trump's rhetoric on the campaign trail, where he has derided illegal immigrants.

"I'm pretty confident that the overwhelming majority of Americans are looking for the kind of politics that does feed our hopes and not our fears, that does work together and doesn't try to divide us, that isn't looking for simplistic solutions and scapegoating," Obama told NBC's "Today" show in answer to a question about Trump.

Asked whether he could imagine Trump as a president giving his own State of the Union address, Obama said: "I can imagine it in a Saturday Night skit," referring to the late-night comedy show. But he added that "anything's possible. And I think, you know, we shouldn't be complacent."

White House spokesman Josh Earnest on Monday blamed an "avalanche of negativity" from Republican candidates for polls that show many Americans see the country as on the wrong track.

Obama is likely to tout last year's Iran nuclear deal and improved U.S.-Cuba relations as achievements, while urging Congress to back criminal justice reform, support the Trans-Pacific Partnership (TPP) trade pact and close the U.S military prison at Guantanamo Bay, Cuba.

He will also likely discuss the U.S. fight against the Islamic State group, which has generated criticism from Republicans as being too meager.

The White House wants to portray Obama as setting the agenda, even on the campaign trail, with goals such as gun control that will reverberate past his time in office. He announced executive actions last week to tighten gun rules.

As usual, first lady Michelle Obama will host people in her seating area during the speech who reflect the president's priorities. This year's guests include Microsoft Chief Executive Satya Nadella and a Syrian refugee who now lives in Michigan.