ROBERTSDALE, Ala. — For a moment, the whole room was on his side.
Scores of voters applauded vigorously on Saturday morning as Jeff Sessions recounted the highlights of his two-decade Senate career as a conservative Republican, like the time he led the charge against Obama-era trade legislation, or the many occasions he blunted his own party’s efforts at immigration reform.
But then, as Mr. Sessions turned to his brief tenure as President Trump’s attorney general — his decision to recuse himself from the investigation into the Trump campaign’s Russia ties, his ensuing banishment from the president’s orbit — his momentum, as it so often did at this juncture of his stump speech, sputtered.
“I know the president’s not happy with me,” Mr. Sessions said of his recusal. “But I’ll tell you: I did the right thing.”
Judging by the fidgeting silence that followed, voters were not so sure.
It was the kind of abrupt tonal shift in crowd reaction that Mr. Sessions has faced time and again in his long-shot bid to reclaim his old Senate seat, which will be decided Tuesday in a runoff election between Mr. Sessions and his Republican opponent, Tommy Tuberville, a former Auburn University football coach. Voters often cheer the ways Mr. Sessions advanced the Trump agenda while in office, only to suddenly recoil at the reminder of his falling out with the man himself. The runoff seems destined to be a final word of sorts on the yearslong Sessions-Trump melodrama, with Alabama Republicans refereeing between a native son and a president they admire.
If Mr. Sessions is defined by his unwavering allegiance to Trumpism despite his rejection by Mr. Trump, Mr. Tuberville is the precise inverse: He has received the president’s full-throated endorsement despite having a spotty record of supporting the president’s agenda, about which Mr. Sessions strains to remind voters at every turn. Mr. Tuberville has argued, for instance, that Mr. Trump’s trade war was “putting a noose” around the necks of American farmers, and has taken other diverging stances from the president on immigration and the United States’ relationship with China.
Those positions haven’t stopped Mr. Trump from unleashing his Twitter feed on the race — praising Mr. Tuberville, of course, but saving the Trumpian flourishes for attacking Mr. Sessions. “Alabama, do not trust Jeff Sessions,” he wrote in May; “Jeff Sessions is a disaster who has let us all down,” he wrote on Saturday.
With polls showing Mr. Tuberville ahead of Mr. Sessions, who won four Senate elections and served from 1997 to 2017, Tuesday’s runoff will also serve as a preview of voter attitudes in a deeply Republican state ahead of Mr. Trump’s re-election bid in November. Are the president’s supporters primarily drawn to him as a function of ideology, which would allow a vote for a policy soul mate like Mr. Sessions, or something closer to a cult of personality, which might necessitate a vote against the banished former attorney general?
Voters in both camps could support Mr. Sessions and feel at peace, argued Cody Phillips, a Republican official in Baldwin County, among the more populous in Alabama.
“If Senator Sessions is elected, he’s going to support Trump and all of his endeavors, because his platform is basically Trump’s platform,” said Mr. Phillips, who is supporting Mr. Sessions.
That a red-state Senate G.O.P. primary would be freighted with such stakes has been a feature, not a bug, of the Trump era. Under any other administration, the nuances of Alabama’s Republican electorate would rarely be newsworthy. But since 2017, when the state made history in electing a Democrat, Doug Jones, to succeed Mr. Sessions, the status of this one Senate seat has shed a bright light on the political psychology of Mr. Trump and his most ardent Alabama supporters and opponents alike.
This is now plainly on display among Alabama voters who are taking their cues from Mr. Trump’s feelings toward Mr. Sessions.
“I never did know what came up between him and Trump,” Carl Williams, 75, of Mobile, said as to why he wasn’t sure he could vote for Mr. Sessions, though acknowledging he didn’t “have anything else against him.” (The winner of Tuesday’s runoff will face Mr. Jones in November.)
Mr. Trump’s disdain for Mr. Sessions stems from the president’s view that the appointment of Robert S. Mueller III, the special counsel who investigated Russia’s influence in the 2016 election, would never have transpired if the former attorney general had not recused himself from the inquiry. And according to multiple current and former White House officials, Mr. Trump’s fixation on the Alabama Senate G.O.P. primary is a reflection of the extent to which the Russia investigation continues to haunt the president — how, even more than the impeachment proceedings, he considers it to be the ultimate taint on his tenure.
From the moment Mr. Tuberville entered the primary, he skillfully channeled the fallout of Mr. Sessions’s recusal, making it the centerpiece of his television ads and catching Mr. Trump’s attention in the process. Mr. Trump grudgingly abided aides’ requests not to involve himself initially in the Alabama race; they were wary of a repeat of 2017, when, in the Republican primary for the Senate seat, Mr. Trump endorsed Luther Strange, who ultimately lost to Roy Moore, a former judge who went on to lose to Mr. Jones after facing accusations of molesting underage girls.
But Mr. Trump took notice of Mr. Tuberville’s hammering of Mr. Sessions — in one recent ad, the former coach says Mr. Sessions “quit on the president” and “failed Alabama” — and how Mr. Tuberville’s platform appeared to involve little more than a promise to always support Mr. Trump.
When Mr. Trump ultimately endorsed Mr. Tuberville on March 10, tweeting that he was a “REAL LEADER,” the president appeared to be embracing not so much a particular agenda but rather the fact that Mr. Tuberville was not his former attorney general.
Mr. Tuberville’s campaign has been startlingly low on specifics, both before and after the runoff race began, a function in part of his regular refusal to engage with the news media. Mr. Sessions, moreover, has challenged Mr. Tuberville multiple times to a primary debate, to no avail; in May, when Fox News’s Chris Wallace extended invitations to both candidates to do just that, Mr. Tuberville declined.
What on-record comments do exist of Mr. Tuberville’s platform indicate a candidate often at odds with Trumpism. He has said that he’s “pissed off” that Mr. Trump has not delivered better health care access to veterans and that, in responding to the coronavirus, the United States “can’t worry about China right now.” Early in the primary, Mr. Tuberville appeared to argue that undocumented migrants crossing the border in search of a job should be offered a pathway to citizenship; both Mr. Sessions and Bradley Byrne, a former congressman who was also a candidate for the nomination, immediately accused Mr. Tuberville of supporting amnesty. (Mr. Tuberville called the accusations “fake news.”)
Yet if there is daylight between Mr. Tuberville and Mr. Trump’s positions, many Republican voters in Alabama do not appear to mind. Throughout the primary, polls have shown Mr. Tuberville besting Mr. Sessions by as many as 20 percentage points. The most recent survey, conducted from July 2 to July 9 by Auburn University at Montgomery, showed Mr. Tuberville with a 16-point lead.
Perry O. Hooper Jr., a former state representative and supporter of Mr. Tuberville, said the race boiled down to the fact that Mr. Sessions had “let the president down.”
“The two things that are popular in Alabama are SEC football and Donald J. Trump,” he said. “Tommy Tuberville won’t let the president down, and to add to that, he’s a former coach of the SEC.”
In some ways, the coronavirus has helped Mr. Sessions make his case in a race where policy has otherwise played little to no importance. Alabama has been hit hard by the virus, with over 51,000 confirmed cases and 1,100 deaths as of Sunday. And in multiple virtual meetings with local Republican groups throughout the runoff, Mr. Sessions has played up his past efforts in the Senate and as a member of the Trump administration to crack down on China, vowing if re-elected to hold the nation accountable for the global spread of the virus.
Mr. Sessions’s focus on the issue, when paired with Mr. Tuberville’s instinct to wave off China’s role in the pandemic, has appeared to help him slightly close the gap with his opponent, according to recent polling. But as Richard Shelby, the senior Republican senator from Alabama, put it in a recent interview, voters may not be paying nearly as much attention to campaigns as usual. “There’s one story in town, and it’s about survival and about health,” he said.
Mr. Shelby, who said he hoped his state would ultimately elect Mr. Sessions, added that “smaller turnout” on Tuesday as a result of virus fears could help his former colleague’s chances. Multiple polls have predicted both Mr. Sessions and Mr. Tuberville prevailing easily in an eventual race against Mr. Jones, though even White House officials acknowledge that Mr. Tuberville, with his lack of experience and growing questions about his brief stint at the helm of a hedge fund, could prove a slightly tougher sell.
Mr. Sessions, for his part, appears to still be optimistic, buoyed in part by surveys that suggest a large number of voters remain undecided. On Saturday afternoon, he dropped by a seafood restaurant in Mobile to introduce himself to people grabbing lunch, passing out copies of a cookbook written by his wife, Mary, and reminding diners of the conservative principles he had long been “willing to fight for.”
In an interview after Mr. Sessions left his table, however, one voter said it would still probably be a “game-time” decision for him. “I like Jeff, I’ll tell you — he did a good job when he was in there before,” said Foster Forbes, a lifelong resident of Mobile, where Mr. Sessions currently lives.
Asked, then, why he remained undecided, Mr. Forbes, who was wearing a camouflage “Trump 2020” hat, paused for a few moments. “Just, you know,” he said tentatively, “the way some people keep talking about him.”