The strange feud between President Trump and Attorney General Jeff Sessions, sparked by the president's irritation over Sessions properly recusing himself from the investigation of Russia's election meddling, isn't just a personal grudge match. It's a battle between Trump and "Trumpism."

Sessions — more than even the president himself — represents the populist, nationalist take on conservatism that laid more conventional candidates to waste in last year's Republican primaries and turned the Rust Belt red last November. As a Republican senator from Alabama, Sessions resisted the drive to get upper chamber Republicans to embrace a substantial increase in legal immigration while legalizing most of the illegal immigrants in the country. In fact, he pushed in the opposition direction, advocating tougher enforcement and what he described as "immigration moderation": "slowing the pace of new arrivals so that wages can rise, welfare rolls can shrink, and the forces of assimilation can knit us all more closely together." Trump largely borrowed Sessions' ideas to formulate his own immigration plan.

As attorney general, Sessions has taken the lead in cracking down on "sanctuary cities" that don't fully cooperate with federal immigration enforcement. Even as he clashed with the president he traveled to El Salvador to highlight the fight against the gang MS-13. "This is the Trump era," Sessions has said when celebrating stepped up immigration enforcement.

Yet nationalism and populism aren't the only hallmarks of the Trump era. A big part of it is Trump himself: the showmanship, the braggadocio, the larger-than-life personality and the tweets. Lots and lots of tweets.

Attorney General Jeff Sessions has taken a VERY weak position on Hillary Clinton crimes (where are E-mails & DNC server) & Intel leakers! — Donald J. Trump (@realDonaldTrump) July 25, 2017 Why didn't A.G. Sessions replace Acting FBI Director Andrew McCabe, a Comey friend who was in charge of Clinton investigation but got.... — Donald J. Trump (@realDonaldTrump) July 26, 2017 ...big dollars ($700,000) for his wife's political run from Hillary Clinton and her representatives. Drain the Swamp! — Donald J. Trump (@realDonaldTrump) July 26, 2017

Sessions is more of a Trumpist than Trump himself. And Trump has proven eminently willing to publicly trash Sessions as part of his flailing frustration at the Russia investigation. It's "hurtful," Sessions said.

I bet it is.

The question now begs. What is more important to our president: his Trumpist platform of cultural and economic nationalism, or the man himself? Is this a movement or a cult of personality?

By prioritizing himself over his movement, Trump seems to have answered that question. In targeting Sessions, Trump has all but declared war on Trumpism.

This debate has also spilled over into the race to fill the remainder of Sessions' Senate term, with the contest coming down to which candidate is the truest supporter of Trump the man.

Rep. Mo Brooks, a Republican congressman seeking the seat, is in many ways committed to Trumpism. He is a tough-talking immigration restrictionist who rails against legislation making it easier for the president to push trade deals without Senate ratification. Brooks even once went further than Trump when he accused the Democrats of waging a "war on whites." The allegation came in an interview with Laura Ingraham, a conservative radio talk show host who has been so fiercely pro-Trump that she has been rumored for White House jobs.

There's just one catch: Brooks hasn't always been all-in on Trump himself. The congressman endorsed Sen. Ted Cruz (R-Texas) in the Republican presidential primaries. Brooks was a tepid Trump supporter during the general election against Hillary Clinton. Brooks has always prioritized Trumpism over Trump.

This has become central to interim Sen. Luther Strange's campaign to hold onto Sessions' seat. Strange, with the support of Republican establishment organs who have themselves kept Trump at arm's length, is hammering Brooks for being a weak supporter of the president.

"I don't think you can trust Donald Trump with anything he says," Brooks says in this ad from a pro-Strange super PAC aligned with Senate Majority Leader Mitch McConnell. "A lot of people who have supported Donald Trump, they're going to regret having done so."

Brooks fought back with an ad vowing to filibuster any spending bill that doesn't contain funding for the president's border wall. He pledged to even read the King James Bible on the Senate floor until voters knew which Republicans were resisting Trump.

The Brooks spot even shows Trump during his campaign announcement uttering the controversial line, "When Mexico sends its people, they're not sending their best."

As Sessions was left to twist in the wind, Brooks doubled down on his Trumpism, not Trump campaign: He defended the attorney general.

"I support President Trump's policies," Brooks declared. "But this public waterboarding of one of the greatest people Alabama has ever produced is inappropriate and insulting to the people of Alabama who know Jeff Sessions so well and elected him so often by overwhelming margins."

"Shame on Congressman Brooks for his lack of faith in President Trump's and Attorney General Sessions' commitment to work together to make America great again," Strange countered.

How will all this end? We are now living in a bizarro world where Breitbart is chastising Trump for leaving Sessions — dubbed a "man who embodies the movement that elected Donald Trump president" — in the lurch and candidates in a state Trump won by 28 points are debating whether it is preferable to be loyal to the president or his platform.

It's the Trump era, alright. But what remains to be seen is whether this era will be defined by the man or the movement.