WASHINGTON (AP) - President Donald Trump, facing sagging approval ratings in a midterm election year, is seeking to rally a deeply divided nation in Tuesday night's State of the Union address with optimism about the growing economy and calls for action on immigration, trade and infrastructure rebuilding.

White House officials say Trump will appeal for bipartisanship, though it's unclear if his rhetoric will be matched by any real overtures to Democrats. Partisanship in Washington has only deepened in the year since Trump has taken office, driven in part by the president's bitingly personal attacks on his political rivals and Democrats' disgust with his policies and behavior.

During a traditional pre-speech lunch with television anchors, Trump said, "Unity is what I'm striving for, to bring the country together."

Tuesday's prime-time address to Congress and millions of Americans watching at home is traditionally a president's biggest platform to speak to the nation. However, Trump has redefined presidential communications with his high-octane, filter-free Twitter account, and there's no guarantee that the carefully crafted speech will resonate beyond his next tweet.

Trump was quiet Tuesday on Twitter, and the White House sought to focus attention on his big speech. Officials said Trump had spent months giving aides "tidbits" about lines he wanted to use in the speech and was assisted in its crafting by national security adviser H.R. McMaster and economy adviser Gary Cohn.

The economy will be the centerpiece of Trump's address, which is expected to run about an hour. Though the current trajectory of lower unemployment and higher growth began under President Barack Obama, Trump argues that the tax overhaul he signed into law late last year has boosted business confidence and will lead companies to reinvest in the United States.

Senate Minority Leader Chuck Schumer said the president should thank his predecessor for the economy during Tuesday's address, but predicted that was unlikely to happen.

"Here are two words we won't hear President Trump say tonight about the economy: 'Thanks, Obama,'" Schumer said.

Considering the strength of the economy, Trump is stepping before the nation in a remarkably weak position. His approval rating has hovered in the 30s for much of his presidency and at the close of 2017, just 3 in 10 Americans said the United States was heading in the right direction, according to a poll by The Associated Press-NORC Center for Public Affairs Research. In the same survey, 67 percent of Americans said the country was more divided because of Trump.

It's unlikely Trump will be able to rely on robust legislative accomplishments to reverse those numbers in 2018. Congress has struggled with the basic function of funding the government, prompting a brief federal shutdown earlier this month that was resolved only with a short-term fix that pushed the spending deadline to Feb. 8.

Against the backdrop of the spending fight, Republicans and Democrats are also wrestling with the future of some 700,000 young immigrants living in the United States illegally. Trump has pledged to protect the so-called Dreamers from deportation but is also calling for changes to legal immigration that are controversial with both parties.

Though Democrats are eager to reach a resolution for the young immigrants, the party is hardly in the mood to compromise with Trump ahead of the midterm elections. Lawmakers see Trump's unpopularity as a key to their success in November, and are eager to mobilize Democratic voters itching to deliver the president and his party a defeat at the ballot box.

Trump also is expected to use the speech to talk about the fate of the U.S. detention center at Guantanamo Bay, Cuba, according to a senior administration official who was not authorized to publicly discuss details of the speech and spoke on condition of anonymity. Trump, who vowed during his campaign to load Guantanamo up with "bad dudes," has long been expected to rescind Obama's 2009 order to close the prison and issue his own stating his administration's policy to keep it open.

Democrats, seeking to set the tone for their election-year strategy, have tapped Massachusetts Rep. Joe Kennedy, the grandson of Robert F. Kennedy, to deliver a post-speech rebuttal aimed at casting his party, not Trump, as the champion of the middle class.

Democrats are also looking to make their mark in other ways. A number of lawmakers are planning to boycott the president's remarks. And some Democratic women plan to wear black to protest sexual harassment, an issue that has tarnished several lawmakers in both parties. Trump himself has been accused of assault or harassment by more than a dozen women, accusations he has denied. The Wall Street Journal reported this month that the president's lawyer arranged a payment to a porn star, Stormy Daniels, to prevent her from talking about her alleged encounter with the future president.

First lady Melania Trump, who has largely stayed out of the spotlight following those allegations, will attend Tuesday's address, according to the White House. She'll be joined in the audience by several guests whose stories amplify the president's agenda, including an Ohio welder who the White House says will benefit from the new tax law and the parents of two Long Island teenagers who were believed to have been killed by MS-13 gang members.

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