President Donald Trump is due to give the annual State of the Union address in the same chamber where he was impeached less than three months ago.
The speech to Congress Tuesday night, with the theme “the great American comeback”, will highlight key election year accomplishments.
Mr Trump will tout US economic and military strength, US media report.
The speech comes as Mr Trump is expected to be acquitted by the Senate in his impeachment trial on Wednesday.
The address – Mr Trump’s third and possibly last, if he loses his re-election bid in November – is due to begin at 21:00, local time.
He is expected to use the address to make his pitch to voters by emphasising optimistic economic figures and criticising rivals.
He is also expected to offer his own plans for healthcare, immigration and economic growth, US media say, contrasting his approach with that of the Democrats he accuses of “socialism”.
During Mr Trump’s time in office, unemployment has dropped to 3.5%, the lowest in half a century – an accomplishment the president has often pointed to as a reason to re-elect him.
However, economic growth and investment has slowed in the past three years.
The president has invited eight special guests to the address – among them are two military veterans, a former Venezuelan police chief, and the brother of a man killed by an undocumented immigrant.
Following the address, Democratic Michigan Governor Gretchen Whitmer will give a rebuttal and congresswoman Veronica Escobar of Texas will follow in Spanish.
At least seven Democratic lawmakers, including Alexandria Ocasio-Cortez and Ayanna Pressley, have announced their intention boycott the State of the Union.
“[Mr Trump] does not embody the principles, the responsibility, the grace, nor the integrity that is required of the president,” Ms Pressley said in a statement.
The presidential address is due to begin hours after senators conclude their speeches in the weeks-long impeachment trial to determine whether Mr Trump should be removed from office.
The president was impeached by the House of Representatives in December on charges of abuse of power and obstruction of Congress. The first charge centres on the allegation that he pressured Ukraine to investigate his political rival, Democrat Joe Biden.
The second charge accuses him of purposefully obstructing the Congressional impeachment investigation.
Mr Trump has denied any wrongdoing. The Republican-led Senate is expected to acquit him, with Mitch McConnell, the majority leader, urging his colleagues to “reject the House abuse of power” with their vote on Wednesday.
“Vote to protect our institutions, vote to reject new precedence that would reduce the [Constitution] framer’s design to rubble,” he said. “Vote to acquit the president of these charges.”
West Virginia Democratic Senator Joe Manchin, a moderate who has voted with Republicans in the past, then called for legislation to censure Mr Trump over the Ukraine matter.
“Censure would allow this body to unite across party lines,” Mr Manchin said. “[Trump’s] behaviour cannot go unchecked by the Senate and censure would allow a bipartisan statement condemning his unacceptable behaviour in the strongest terms.”
A Gallup poll released on Tuesday found Mr Trump’s approval ratings reach a personal best of 49% ahead of the address.