The voice echoing through the speaker on my phone was deep, halting, and offensive.

The message lasted a full minute and eighteen seconds. It included derogatory and racist insults directed at my family and me.

I could barely stand to listen.

The voicemail – which arrived amidst a virtual barrage of attacks by phone, email, and social media – left me rattled.

What offense had I committed to become the target of such vitriol?

On October 4, I published an op-ed – U.S. ignores small African terrorist group IPOB at its peril – in The Washington Times. The article called for the inclusion of a militant, separatist group in Nigeria, Indigenous People of Biafra (IPOB), on the U.S. State Department list of Foreign Terrorist Organizations.

It was hardly a radical proposal. The group meets the definitional criteria for terror listing and their malign efforts to coerce and intimidate those that oppose their political and social goals are legendary.

My assessment ran in the print edition of The Washington Times a day later, earning attention by BBC News shortly thereafter.

Contrary to claims that IPOB is a “nonviolent” movement with only “peaceful” intentions, the Eastern Security Network (ESN) – the group’s 50,000 strong paramilitary wing – has engaged in a series of escalatory attacks on Nigerian security personnel in recent months. The Council on Foreign Relations reports “ a 59% increase in attacks and a 344% increase in deaths” since the establishment of ESN late last year.

IPOB’s global network of supporters is equally belligerent.

Within hours of publication, I found myself in the movement’s crosshairs – the latest target of a coordinated take-down operation designed to bully me into backing down from my policy prescription. Local and federal law enforcement took notice.

My work as a counterterrorism scholar has long since left me accustomed to criticism. I have researched and written about rogue actors and repressive regimes on hundreds of occasions in dozens of outlets. The work has taken me around the globe and behind enemy lines.

But the combination of racist rhetoric, ethnic superiority, religious bigotry, and defamatory statements issued by IPOB activists and Biafra’s sympathizers was unique – even for someone that covers militant sub-state actors.

I was tagged in thousands of social media posts that coupled disinformation with libelous, ad hominem attacks intended to silence me by damaging my reputation.

My phone rang day and night. Hundreds of emails flooded my inbox. My home address was circulated on social media. So too was my spouse’s work address.

I was derided as a “fake professor,” despite being easily identifiable as a tenured scholar that leads a nationally-ranked school of public and international affairs.

IPOB supporters were encouraged to complain to university officials and given scripts to follow.

The harassment was extensive.

I was falsely pronounced a Muslim, as if it were a crime. My national origin was questioned. My wife – a Black woman from Botswana – was incorrectly cast as Fulani, a naked reference to an ethnic group scattered across West Africa that has long challenged Igbo dominance in Nigeria.

And, without a shred of evidence, I was repeatedly accused of accepting bribes from Nigerian authorities – some going so far as to manufacture sensationalist details of cash-filled envelopes.

Scores of complaints were lodged with the Offices of the Provost and President at my university. Human Resources also took angry calls from IPOB supporters insisting on my removal.

When The Washington Times ignored calls to retract my article, IPOB supporters falsely claimed my commentary had been taken down. BBC News corrected the disinformation – in Igbo, no less.

Even my letterhead was mimicked online with false assertions released under my name.

The only substantive criticism I witnessed came from an individual whose signature identified him as a Department of Justice registered Foreign Agent acting at IPOB’s behest.

That IPOB supports a virtual army of paid hands who collect lucrative fees for peddling the group’s propaganda speaks volumes.

To be clear, the abusive tactics employed by IPOB militants, and their global network of sympathizers, are not new. And I am just one of many targets.

Biafra’s self-appointed leader, Nnamdi Kanu, once in exile and now under detention following his arrest by Interpol, has trafficked in incendiary rhetoric and division for so long that he has given rise to a generation of cultish followers.

Expecting supporters of Biafra’s imagined Republic to value academic freedom or support free speech may be too much to expect. But bullying American scholars or intimidating U.S. officials is unlikely to earn them allies.

The Biden administration would be wise to support Nigeria’s efforts to keep the country united by rejecting calls for a referendum and turning up the heat on IPOB separatists. Doing so would free resources that could be better leveraged against the principal threat of concern to both Washington and Abuja – Boko Haram in North-East Nigeria and the Lake Chad region.

In remarks to the U.N. General Assembly last month, Nigeria’s President Muhammadu Buhari prioritized the urgent need to address the growing presence of transnational terrorists with global connections on the African continent: “Nigeria will continue to work closely with U.N. counter-terrorism bodies and entities with a view to bringing this scourge to an end,” he said. “Nigeria has spared no effort in addressing the challenges of terrorism posed by the activities of Boko Haram.”

But over the past twelve months, Boko Haram and other Al Qaeda-affiliated groups across the volatile Sahel region have regained operational strength. That the African continent is quickly becoming a haven for global terrorism is worrisome.

Long a partner on counterterrorism operations in West Africa, U.S. officials can help Nigeria prioritize efforts to train their sights on Boko Haram by rejecting IPOB’s secessionist agenda, malevolent influence operations, and incendiary intimidation tactics.

Prof. Ivan Sascha Sheehan is the executive director of the School of Public and International Affairs at the University of Baltimore. Opinions expressed are his own. Follow him on Twitter @ProfSheehan.