WASHINGTON — America's divisions will enter into burning focus Tuesday when President Donald Trump delivers the annual State of the Union speech to Congress, just ahead of his expected acrimonious impeachment acquittal.

The State of the Union is a grand set-piece in the US political calendar, a rare occasion when bitter opponents traditionally observe a truce while the president lays out a vision for the future.

But Trump will drive up Pennsylvania Avenue to the Capitol at a time of rancor arguably unmatched for decades — and likely to worsen as the November presidential election approaches.

The White House promises Trump will be "relentless" in talking up the US economy and the "blue collar boom" when he takes to the podium at around 9:00 p.m. (0200 GMT Wednesday).

"I think the speech is going to have a very optimistic tone," a senior administration official told reporters.

The reality is that Trump will be entering a chamber where only last December the Democratic-led House of Representatives, the lower chamber, impeached him for abuse of power and obstructing Congress.

And he'll be looking out over a group of legislators where only a narrow Republican majority in the upper chamber Senate is likely to save his job when a verdict vote comes Wednesday.

The speech could in theory be an opportunity to reach out and heal a nation boiling over in mistrust.

Trump could express regret for what even several of his own Republican senators agree was wrongful behavior in pushing Ukraine to open a questionable corruption probe against one of his main Democratic presidential opponents, Joe Biden.

Or he could seek to calm the waters by entirely avoiding the topic of impeachment, just as Bill Clinton did during his post-impeachment State of the Union in 1999.

White House officials say they don't know what he'll do.

"It's never safe to assume anything," the administration official said, when asked if impeachment will be kept out of the speech.

Republican senator, Roy Blunt, told The New York Times that Trump should "avoid" the "i" word.

"It's an opportunity to move on," Blunt said, while acknowledging that the real estate tycoon and reality TV show performer is not the type to turn down the volume.

"The other option is to address it head on — and he is often a head-on kind of guy."

Right before the speech on Tuesday, the Senate will be finishing up the impeachment trial. Closing arguments took place Monday.

But even though the proceedings will end with Wednesday's verdict vote, the Democrats say they'll keep going at Trump.

"President Trump's constitutional crimes, his crimes against the American people and the nation remain in progress," said Democrat Val Demings, one of the impeachment managers prosecuting the case before the Senate on Monday.

"The plot goes on, the scheming persists and the danger will never recede," Adam Schiff, the lead impeachment manager, said, challenging Republicans to "speak the awful truth."

While the Senate is safe ground for Trump, the Democratic majority in the House is expected to continue aggressive probes of Trump's alleged corruption.

The State of the Union address adds further drama to a packed political diary ahead of the November presidential election.

The Democratic race for the party nomination kicked into high gear this week with the Iowa Caucasus on Monday. The New Hampshire primary takes place in a week and from there the pace will accelerate.

Several of Democratic contenders — including Senate jurors Amy Klobachar, Bernie Sanders and Elizabeth Warren — will be sitting right there in the audience on Tuesday.