In response to the assassination, Congress passed the Immigration Act of 1903, a law meant to keep several classes of people, including anarchists, polygamists, and prostitutes, from immigrating to the US. The legislative body added several similar laws in the years that followed.
Writing about anarchism in 1908, Roosevelt certainly seemed to consider the ideology a serious threat, stating that "when compared with the suppression of anarchy, every other question sinks into insignificance." In practice, however, the laws of the era had almost no impact on anarchism in the US: For the first decade that it was in effect, only 15 alleged anarchists were denied entry to the country.
The panic over anarchists and foreign radicals in the lead up to the first World War did, however, present an opportunity for both the president and Congress to standardized federal immigration laws and add new restrictions. In 1917, with the US poised to enter the conflict in Europe, Congress imposed a literacy test for new immigrants, the first immigration restriction applying to all newcomers.
So by dubbing President Obama an anarchist, Pearce is tapping into the talking points that helped fuel restrictionist sentiment nearly a century ago. Of course, that may have been totally unintentional, as Workers Solidarity Alliance member Lucas Alvarez suggests:
"I think he's just trying to get some voters who want a tougher stance on immigrants and make Obama seem like some wild-haired hippie."