“I wanted to try to find middle ground,” Mr. LaCorte said. “Unfortunately, the things that work best right now are hyperactive politics. On one hand, that's at odds with what I want to do. But you can be more successful by playing the edgy clickbait game.”

He added: “Where does that line turn from good business to ‘Eh, that’s sleazy’ ?”

Exploiting American cultural and political fissures to drive traffic to his websites has worked wonders. At last count, Mr. LaCorte had more than three million followers on the social network and 30 million unique visitors to his sites. Even he couldn’t believe his success.

“One day I woke up and more than 1 percent of Americans were following my sites,” he said.

Intentionally or not, the sites are mimicking Kremlin interference in 2016, when Russian operatives used fictitious personas to inflame American discord over Benghazi, border security, gun control and Black Lives Matter.

American officials have warned that Russia is laying groundwork for interference in 2020. In a rare joint statement this month, officials at the Department of Homeland Security, the F.B.I., the National Security Agency and other agencies warned that Russia, China, Iran and other nations would seek to interfere in the 2020 election through social media, disinformation and cyberattacks. The announcement was intended to assure Americans that the government was prepared.

What is less clear is how officials plan to address the growing and increasingly profitable marketplace for politically divisive content that is being operated by Americans. In this case, with help from Macedonia.

The spreading of politically divisive content or even blatant disinformation and conspiracy theories by Americans is protected free speech. Security experts said the adoption of Russian tactics by profit-motivated Americans had made it much harder to track disinformation.