BIRMINGHAM, Ala. — Southern Gothic is a literary genre and, occasionally, a political style that, like the genre, blends strangeness and irony. Consider the current primary campaign to pick the Republican nominee for the US Senate seat vacated by Jeff Sessions. It illuminates, however, not a regional peculiarity but a national perversity, that of the Republican Party.

In 1985, Jeff Sessions was nominated for a federal judgeship. Democrats blocked him, calling him racially “insensitive.” In 1996, he got even by getting elected to the Senate. Twenty years later, he was the first senator to endorse Donald Trump, who carried Alabama by 27.7 points.

Sessions, the most beloved Alabaman who isn’t a football coach, became attorney general for Trump, who soon began denouncing Sessions as “beleaguered,” which Sessions said was because Trump was ridiculing him as “weak” because he followed Justice Department policy in recusing himself from the investigation of Russian involvement in Trump’s election.

On Aug. 15, Alabama’s bewildered and conflicted Republicans will begin picking a Senate nominee. (If no one achieves 50 percent, there will be a Sept. 26 runoff between the top two.) Of the nine candidates, only three matter — Luther Strange, Roy Moore and Rep. Mo Brooks.

Strange was Alabama’s attorney general until he was appointed by then-Gov. Robert Bentley to Sessions’ seat. Bentley subsequently resigned in the wake of several scandals that Strange’s office was investigating — or so Strange’s successor as attorney general suggests — when Bentley appointed him. The state Ethics Commission recently postponed a hearing into campaign finance violations until Aug. 16, the day after the first round of voting.

Twice Roy Moore has been removed as chief justice of the state Supreme Court. In 2003, removal was for defiance of the US Supreme Court regarding religious displays in government buildings. Re-elected, he was suspended last year for defiance of the US Supreme Court’s decision regarding same-sex marriages.

Yet Brooks is the focus of ferocious attacks on behalf of Strange, financed by a Washington-based PAC aligned with Senate Majority Leader Mitch McConnell.

They stress some anti-Trump statements Brooks made while chairman of Ted Cruz’s 2016 Alabama campaign. For example, Brooks criticized Trump’s “serial adultery,” about which Trump has boasted. The PAC identifies Brooks, a conservative stalwart of the House Freedom Caucus, as an ally of Nancy Pelosi and Elizabeth Warren. Another uses Brooks’ support for Congress replacing the 2001 Authorization for Use of Military Force with an updated one, and his opposition to interventions in Libya and Syria, to suggest that Brooks supports ISIS.

Brooks contributed to Trump’s general-election effort, and says he supports Trump’s “agenda,” including potentially its most consequential item — ending Senate filibuster rules that enable 41 senators to stymie 59. Strange sides with McConnell against Trump in supporting current rules.

Yet the PAC’s theme is that Brooks’ support of Trump is insufficiently ardent. Such ardor is becoming the party’s sovereign litmus test.

A recent poll had the three in the 20s, with Moore leading: The PAC’s attacks are driving some Brooks voters to him. Among voters who say they’re familiar with all three, Strange is third. A runoff seems certain, and if Moore (sometimes called “the Ayatollah of Alabama”) is in it and wins, a Democrat could win the Dec. 12 general election.

“Anything that comes out of the South,” said writer Flannery O’Connor, a sometime exemplar of Southern Gothic, “is going to be called grotesque by the Northern reader, unless it is grotesque, in which case it is going to be called realistic.”

But, realistically, Alabama’s primary says more about Republicans than about this region. A Michigan poll shows rocker-cum-rapper Kid Rock a strong potential Republican Senate candidate against incumbent Debbie Stabenow. Rock says Democrats are “shattin’ in their pantaloons” because if he runs, it will be “game on mthrfkrs.”

Is this Northern Gothic? No, it is Republican Gothic, the grotesque becoming normal in a national party whose dishonest and, one hopes, futile assault on Brooks is shredding the remnants of its dignity.