White nationalist gunmen are a worldwide 'contagion' -- like ISIS: Ex-FBI terrorism expert

White supremacist are drawing inspiration from one another to commit acts of terrorist violence, according to former FBI agent Clint Watts, mush the same way ISIS does.

A 21-year-old gunman who killed 20 and wounded dozens more in El Paso cited a manifesto written by the gunman who opened fire in March at a New Zealand mosque, which also inspired a California synagogue killer a month later, reported The Daily Beast.

Their hateful ideology is rooted in a conspiracy theory promoted in the 2011 book, "The Great Replacement," by French author Renaud Camus, who warned white people are being deliberately “replaced” through mass immigration with the assistance of liberal elites.

“They all cite each other,” said Watts, a former FBI agent and current distinguished research fellow at the Foreign Policy Research Institute. “(Saturday's) El Paso shooter cited Christchurch. Then he talked about how a month ago, he started to think about an attack. That’s really a short time, which makes it even more impossible for law enforcement to get in front of it."

Watts said white supremacist terrorists have touched off a wave of violent attacks using similar tactics as Islamic State militants, who recruit vulnerable young men online and create an echo chamber of extremist rhetoric.

“Because of those successful attacks, you’d see a wave of inspired attacks, meaning that there are often one, two, three people already thinking about doing an attack,” Watts said. "They mobilize because they want to get into the media storm. They want to be part of that phenomenon. It becomes a contagion.”

Watts has been sounding the alarm since before President Donald Trump's election, but he said media coverage of white supremacist violence remains passive.

“What’s remarkable that our response is just, ‘Eh, this guy is a bad apple, he’s crazy,” he said. “But in the summer of ‘16, I would be on 'Morning Joe' every single day talking about an attack that would be the equivalent in Bangladesh.”