One day this summer, in the midst of this escalation, while he was scrolling through political sites on his phone, a Democratic operative in Lansing named Bob McCann came across a fifteen-second video advertisement attacking Whitmer. McCann spent several years working as Whitmer’s chief of staff when she was the minority leader of the state senate, and he considers her a close friend. When he encountered the ad again, he unmuted it. “Who is Gretchen Whitmer?” a female narrator asked, over a screen split between an image of Whitmer speaking and stacks of cash. “She funds her campaign with big money from big drug and big insurance-company executives. No wonder Gretchen Whitmer opposes single-payer health care.” To McCann, it seemed likely that allies of El-Sayed or Thanedar had paid for the ad, because it so exactly echoed the lines of their campaign.

On his phone, McCann took three screenshots of the ad, making sure to capture the final frame, which said, in small type, “Paid for by Priorities for Michigan.” McCann has been involved in Democratic politics in Michigan for almost twenty years, but he had never heard of the group. He texted a few other Democratic operatives. “No one had any clue,” he told me. He searched for Priorities for Michigan on the Michigan secretary of state’s Web site, which lists all campaign committees and pacs registered in the state, but found nothing. McCann tried Googling “Priorities for Michigan,” but that didn’t work. “Every politician in the state gives speeches about their ‘priorities for Michigan,’ and those were all the hits,” he said. Whitmer was being attacked for shadowy corporate ties by a group that itself left no trace.

McCann, searching for the source of the Priorities for Michigan ad, found another in the screenshots: the group had listed a post-office box in Lansing. He Googled it and got hit after hit for another political group, League of Our Own, which seemed to be promoting female candidates. (There was no mention of Priorities for Michigan on the active version of the Web site, but, on Google’s cached version, McCann found “Paid for by Priorities for Michigan,” along with the same post-office-box number.)

Looking at the group’s Web site, he realized that he knew just about all of its officers and supporters. “It was a Who’s Who of Republican politics in Michigan,” he said, including several state representatives, a conservative political consultant named Tony Daunt with close connections to the DeVos family, and Jase Bolger, the former speaker of the Michigan House, who once refused to allow a female Democratic legislator to speak on the chamber floor because she had used the word “vagina” in a debate about reproductive rights. In McCann’s view, these were the same conservatives who had been undermining liberal female politicians for years. Now, it seemed to him, if they were indeed behind Priorities for Michigan, they were using progressive ideas to divide Democrats, in the primary and perhaps in the general election. “If they had not put the post-office-box number on the ad, no one could have connected Priorities for Michigan to anything at all,” McCann said.

McCann took his discovery to the Detroit News, which reported, on July 5th, that “a mysterious group” running online ads attacking Whitmer from the left “appears to have connections to several Michigan Republicans.” But the story remained at the level of supposition: League of Our Own did not respond to an e-mail, and Daunt and Bolger did not return the paper’s calls. (They also did not return mine.) Public records indicate that when Priorities for Michigan bought time on a Detroit radio station—for another ad claiming that Whitmer “sides with big drug and insurance-company executives” and against “our communities”—it listed only one officer, Eric Doster, the general counsel of the Michigan Republican Party from 1992 to 2017, and perhaps the preëminent conservative election lawyer in the state. Doster, too, did not return my requests for comment.

It appeared that Republicans had picked up on the tension El-Sayed had pinpointed: between the Democratic Party as it has been and as it aspires to be. “If I were Abdul El-Sayed, and I could see that the DeVoses were using my talking points, I would wonder about what I was doing,” McCann told me. But, of course, he didn’t know that the DeVoses were involved, any more than El-Sayed’s campaign knew that Blue Cross Blue Shield was behind Build a Better Michigan. During the past decade, Democrats have fixed on activist billionaires and corporate interests—the Kochs and the DeVoses, Exxon and Goldman Sachs—as their true enemies, heightening anger among their partisan base. But, in the 2016 election and, now, in this year’s primaries, that anger is coming to haunt the Democratic establishment.