DALLAS — Republicans are flocking to Texas for an unprecedented national midterm convention headlined by President Trump to turn out voters in the congressional races that will dictate the course of his final two years in office — though some Republicans are nervous it could backfire.

The two-day gathering — nicknamed “Trump-a-Palooza” — offers free publicity for Republicans as they attempt to brand Democrats as “socialists” and features a slew of fundraising events to help the party boost its already large cash advantage to beat back bleak polls pointing to a possible November wipeout.

Trump will speak on Wednesday and Thursday night after 9 p.m. eastern time — with Vice President JD Vance also giving remarks Thursday.

Earlier slots will feature Trump administration officials touting policy wins and give lesser-known figures a moment in the spotlight to court donors and build momentum before a national audience.

Many speakers plan to frame the election as a choice between Trump’s record and the ascendant socialist wing of the Democratic Party, sources said, as Republicans try to defy the historical trend of a president’s party losing seats in a midterm.

“It’s electrifying. People are excited. People are ready to go,” Republican National Committee Chairman Joe Gruters told conservative media personality Benny Johnson Tuesday, predicting that as many as 60,000 people will show up, including approved members of the public.

“We have 109 speakers, and it’s going to be an absolutely incredible event, and we’ll have a few surprises. If we’re going to win the midterms, we have to do things differently.”

Gruters said “it was President Trump’s idea, and while most conventions take years to prepare, we’ve turned this vision into a reality in just the last 60 days.”

The event, however, is a gamble — with some Republican consultants close to the administration telling The Post that the event could harm vulnerable candidates by making the Nov. 3 election all about Trump at a time when polls show him with low approval ratings.

It could also become embarrassment if the NFL’s opening nights — on Wednesday and Thursday — claim more viewers than the commander-in-chief.

“I’m all in on Republicans winning. But midterms are referendums on the president, and having the same Republicans talk even more about the administration isn’t increasing our numbers,” one GOP consultant said.

A second operative close to the White House said “the whole thing is dumb, especially to do [it] on the two opening nights [of the NFL season].”

On Wednesday night, Trump will compete for the nation’s attention while the New England Patriots and the Seattle Seahawks clash in a Super Bowl rematch in a game that airs on NBC. The following night, the convention goes up against the San Francisco 49ers-Los Angeles Rams matchup on Netflix.

‘Haters will be pleasantly surprised’

Trump is expected to rattle off a variety of feats that he often claims should deliver Republicans a mandate for the remainder of his term — including strong-arming pharmaceutical companies into lowering prices and pushing through Congress new tax breaks on tips, overtime and Social Security payments.

“Haters will be pleasantly surprised by the amount of policy focus in the speeches,” said a person involved in planning the event.

“They will mention the president and the Republican Congress’ victories — policy wins and tax cuts.”

Incumbent presidents almost always lose House seats in the midterms, with George W. Bush the most recent to buck the trend in 2002 as he avenged the 9/11 attacks a year prior.

The GOP currently holds a tenuous five-seat edge — and the party lost 41 House seats in 2018 during Trump’s first term.

Trump, aware of the historical context, devised the convention — Democrats are not hosting their own midterm convention — as a way to upend the expected outcome.

Although a redistricting war gave Republicans an edge in a handful of districts, economic concerns in particular have dragged on the party in power — with the Iran War causing an uptick in inflation and gas prices.

The prime time slots after 8 p.m. eastern time go to a mix of well-known and up-and-coming figures.

On Wednesday, the coveted window includes Medicare and Medicaid chief Dr. Mehmet Oz, Florida gubernatorial candidate Rep. Byron Donalds, Arizona House candidate Jay Feely, Michigan House candidate Mike Bouchard and Treasury Secretary Scott Bessent.

The Thursday primetime slot includes Health and Human Services Secretary Robert F. Kennedy Jr., Dallas Mayor Eric Johnson, former White House press secretary Karoline Leavitt and Donald Trump Jr.

“Everybody wants to be there, but we’re really asking only those Candidates that are in tight Races, a little up, a little down, or even, to speak,” the president wrote on Truth Social Tuesday.

“We want to save the ‘stage’ for them. We don’t need people who are up 45 points, and have been in office for 30 years, as much as we love them all!”

Candidates in tight races have chosen different approaches to the convention, which is shorter than a standard presidential-year summit.

Perennially vulnerable Maine Sen. Susan Collins and South Dakota Sen. Mike Rounds, whose Democrat-backed independent challenger claims to have pulled even in internal polling, are skipping the convention altogether. 

Both Collins and Rounds have distanced themselves from Trump’s weeks-old trade war with Canada, noting the likely effect of retaliatory tariffs on their states’ exports.

But others in competitive races aren’t just showing up — they are appearing on stage.

New York Rep. Mike Lawler, whose district was won by Democratic presidential nominee Kamala Harris in 2024, and Ohio Sen. Jon Husted, who faces a tough challenge from Democratic former Sen. Sherrod Brown, are among the speakers.

So too is Texas Attorney General Ken Paxton, who is neck-and-neck with Democrat James Talarico in the state’s hotly contested Senate race. Paxton, who has faced a litany of scandals, could benefit from Trump’s embrace in the heavily Republican state.