Over the past several months — at congressional hearings, in a report by the Soufan Center, and in a letter to the State Department signed by 40 members of Congress — we have documented the existence of a global network of white supremacist extremists that stretches across North America, Europe and Australia. White supremacists today are organizing in a similar fashion to jihadist terrorist organizations, like Al Qaeda, in the 1980s and 1990s. They transcend national barriers with recruitment and dissemination of propaganda. And just as jihadists exploited conflicts in Afghanistan, the Balkans and Syria, so too are white supremacists using the conflict in Ukraine as a laboratory and training ground.

Yet despite these profound similarities, United States law has not caught up to the new threat we face. International white supremacist groups are still not designated as foreign terrorist organizations, which means our law enforcement and intelligence agencies cannot access the full suite of tools available to them in countering groups like ISIS and Al Qaeda.

A few examples lay bare the extent of this tangled, transnational web.

The Australian who in March last year murdered 51 worshipers at mosques in Christchurch, New Zealand, claimed in his manifesto that he had traveled to Ukraine; during the attacks he wore a symbol used by the Azov Battalion. The F.B.I. director recently warned that American extremists, too, are traveling overseas for paramilitary training. Among those who have trained with Azov are several of the men responsible for fomenting violence at the Unite the Right rally in Charlottesville, Va., in August 2017. James Alex Fields Jr., who murdered a protester with his car, was a member of Vanguard America, a group with ties to the British network that celebrated Thomas Mair, the far-right extremist who assassinated the British legislator Jo Cox in 2016.