Donald Trump is expected to announce his 2024 presidential campaign on Tuesday night as planned, according to multiple sources close to the former US president, inserting himself into the center of national politics as he attempts to box out potential rivals seeking the Republican nomination.

Trump will deliver at 9pm ET a speech from the ballroom at his Mar-a-Lago resort, where he recently hosted a subdued midterm elections watch party, and detail several policy goals that aides hope could become central themes of the presidential campaign.

Trump’s remarks were being finalized late into the night with a pair of speechwriters and his political team, the sources said, with aides keen for the former president to convey a degree of seriousness as he seeks voters to elevate him to a second term in the White House.

The political team at Mar-a-Lago are aware nonetheless that Trump has a penchant for veering off script and delivering news as he pleases, often fixating on grievances over debunked election fraud claims that have historically done him no favors.

Still, Trump appears to know that after the disappointing Republican results in the midterm elections, he is perhaps at his most politically vulnerable since the January 6 Capitol attack, and faces a critical moment to ensure he does not get discarded by the rest of the GOP.

The former president has been forced to shoulder some of the blame for poor performances in key races, including in Pennsylvania, where his handpicked Republican candidate, Mehmet Oz, lost to Democrat John Fetterman in a contest that allowed Democrats to keep the Senate majority.

That prompted some of his trusted external advisers to urge him to delay announcing his 2024 candidacy until after the Senate runoff election in Georgia, where another of his Republican candidates, Herschel Walker, trailed Democratic incumbent Raphael Warnock in a close general election.

The group urging a delay feared that Trump could sink the Senate runoff for Republicans as he is widely considered to have done in 2020, when he focused on his own angry complaints about the 2020 election rather than helping the party’s two candidates, who both ended up losing.

But Trump was told by top members of his political team to stick to the original schedule, the Guardian has previously reported, since delaying the announcement would give him the appearance of being wounded by the disappointing results in the midterms and would make him look weak.

The calendar would also complicate an announcement later in the year, he was told, since waiting until the week after the runoffs in December would be the final week before Christmas – which would mean only several days of cable news coverage before the holiday season.

A further consideration may have also been on Trump’s mind: the idea – though likely misguided – that declaring his candidacy would provide protection from the justice department as prosecutors investigate whether he criminally retained national security documents at Mar-a-Lago.

Trump was swayed by the “go” advisers just a few days after election night for the midterms, the sources said. The decision was communicated as final and several “delay” advisers, like Jason Miller, reversed course to publicly support a Tuesday announcement.

But Trump has remained unsettled about the possibility that Florida governor Ron DeSantis, who won re-election last week in a landslide, may consider a 2024 White House bid of his own – the one potential candidate he considers a genuine threat.

To get ahead of rivals, reinforce his status as the frontrunner for the Republican nomination, and if nothing else, seize the limelight, Trump has been itching for some time to launch his 2024 campaign and has already started laying the groundwork for the effort.

The former president wanted to announce his candidacy at his final rally before the midterms when he stumped for Senate candidate JD Vance in Ohio, one of the bright spots for Trump’s endorsements given Vance’s comfortable victory.

Instead, having been told to hold off his 2024 campaign launch for fear he could turn out more Democratic voters in the midterms, Trump ended up announcing that he would announce his candidacy – which his political team later rued as perhaps having the same effect.