"We swear that on November 3 we will go out and vote," Trump prompted his followers at the Dallas convention as it wound up on Thursday.
Normally party conventions are only held ahead of a presidential election, and this was the first Republican convention ahead of US midterm elections. The Democratic Party is not holding one.
About one-third of the Senate and the entire House of Representatives are up for election in the midterms. With Republicans holding narrow majorities in both chambers, individual seats could determine control of Congress.
During the final day of the convention, Trump, who is struggling with poor approval ratings not least due to the war on Iran, told his supporters to imagine that he is on the ballot.
"Please act as if I were running," Trump, 80, told the crowd. The walls of the huge event were plastered with numerous pictures of the president.
While those in attendance burst into cheers - almost at the push of a button - whenever Trump or other Republicans on stage praised his agenda, in reality many seats were empty, especially on the first day, though Trump raved on his Truth Social platform that the convention had been a "huge, sold-out success."
Some Republicans deliberately decided against attending and instead continued campaigning in their districts or states.
Outside of Trump's MAGA base, the president remains deeply unpopular. If Republican candidates are seen at his side in the run-up to the midterms, they could risk being held jointly responsible for his policies.
Complicating the picture for the Republicans is the ongoing war with Iran, which is unpopular among a majority of Americans.
The war's resulting in higher fuel prices is also an issue. Petrol price watching portal Gasbuddy reported record US diesel prices on Thursday - of $6 per gallon - up $2.30 on a year ago.
And since US trucks run on diesel, prices for food and goods could likely increase further. Economists also see the current US tariff policy as adding to inflation.
The tariff dispute with Canada, which escalated further in recent days, particularly affects northern US states, putting Republican candidates there in a difficult position.
During the convention, the Republicans painted a bleak picture of the country's future if the political opposition succeeds in the congressional elections.
Time and again, Republicans attacked left-wing Democrats who have notched up successes in party primaries ahead of the midterms, slamming their opponents as "radical," "crazy," and "Communists."
It is perhaps no coincidence that the convention was held in Texas, where the party is hoping to help Trump-backed Senate candidate Ken Paxton.
Normally Texas, a deep red state, would be expected to easily elect whichever Republican is on the ballot, but Democratic candidate James Talarico is seen as a strong challenger. If he wins, he would be the first Democratic senator from Texas in more than three decades.
That things are starting to slip for the Republicans was also shown by Trump's promise to give every adult US citizen $5000 should the Republicans retain their majorities in both chambers.
The proposal would cost more than $1 trillion, about as much as the entire US defence budget, and is regarded as neither politically nor financially realistic.
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