Originally Published: 27 JUL 21 06:00 ET

By Gregory Krieg, CNN

(CNN) -- Former President Donald Trump's influence with Texas Republicans faces a stern test on Tuesday as voters in the state's 6th Congressional District choose between a pair of GOP candidates in a runoff to fill the late Rep. Ron Wright's seat.

Susan Wright, the widow of the congressman -- who had cancer and died following a Covid-19 diagnosis in February -- finished first in the May 1 special election after picking up Trump's support shortly before the end of early voting. But the former aide to GOP state lawmakers failed to win a majority, which spurred a one-on-one contest with the second-place candidate, state Rep. Jake Ellzey. The district includes Ellis, Navarro and parts of Tarrant counties.

The campaign has turned less on any specific issue -- both are in line on all major conservative policy priorities -- than on clashing endorsements. Wright has Trump's support, while Ellzey enjoys the backing of some high-profile Texas Republicans with ties to the former President. And because Democrats were locked out of this final round, the results on Tuesday will not make any immediate impact on President Joe Biden's agenda in Washington, where Democrats hold a narrow House majority.

Despite the diminished national stakes, Trump dialed up his involvement as the race reached its final stages, recording a late robocall for Wright that touts her as "strong on immigration" and promises she will "cut your taxes and cut them even further than we've done." His super PAC, Make America Great Again Action, spent $100,000 as early voting ended and Election Day approached. And on Monday, Trump released a new statement of support and took part in a virtual event for Wright's campaign.

Wright also has the backing of the Club for Growth, an anti-tax group, which has spent hundreds of thousands of dollars questioning Ellzey's conservative credentials. Texas' Sen. Ted Cruz endorsed Wright in early May. Rep. Elise Stefanik of New York, a Trump favorite and the third-ranking Republican in the US House, has been a booster.

Ellzey, a decorated former Navy pilot and veteran who lost a 2018 primary to Ron Wright, also has considerable GOP firepower on his side. He outraised Susan Wright by more than 2-to-1 and has the backing of former Texas Gov. Rick Perry, Trump's first energy secretary, and US Rep. Dan Crenshaw of Texas, who recorded a video for the campaign in late June responding to a series of what he called "dishonest" attacks, including the suggestion that Ellzey is a "Never Trumper."

"This is not true. He has always supported President Trump, voted for him twice, long supported him," Crenshaw said. "They're saying this because he got a donation from somebody who's a 'Never Trumper.' He can't control that. What's he supposed to do, just return money?"

Ellzey, who has sidestepped direct criticism of Wright, posted an ad earlier this month titled "Trump Supporters Love Jake Ellzey." The nearly three-minute video features Trump voters from the 6th District talking up Ellzey and connecting him to Trump's legacy -- though it notably does not make mention of Trump's lies about the 2020 election.

Earlier this month, Ellzey joined Trump, Texas Gov. Greg Abbott, a group of Republican House members from around the country and other GOP leaders at the southern border, where the former President mixed criticism of his successor's immigration policies with more false charges about his general election defeat last year.

Early voting in the special election runoff began on July 19 and ended on Friday. As of Thursday, turnout -- including early and mail-in votes -- was a little more than 12,000. Polls close on Tuesday at 7 p.m. CT. The total for the initial round, completed on May 1, was about 78,500. Wright captured less than 20% of that vote. Ellzey finished with 13.85%.

While Trump's popularity with Texas Republicans remains strong, the former President won the Republican-leaning 6th District by only 3 percentage points in 2020, down from 12 points four years earlier. Despite that sign of Democratic momentum in the district, the top Democratic candidate in May's first round of voting placed third, missing out on the runoff by fewer than 400 votes, guaranteeing that the seat would remain in GOP hands.

The winner, though, will not have much time to get comfortable on Capitol Hill. The seat will be up for grabs again during next year's midterm elections, with the primary scheduled for March 1.