After winning a court victory with his initial travel ban that targeted some predominantly Muslim countries, U.S. President Donald Trump has followed up with another sweeping measure, this time blocking immigration from Eritrea, Kyrgyzstan, Tanzania, Myanmar, Sudan, and Nigeria. However, none of the countries has as much to lose from the decision than Nigeria.

The restrictions announced on Jan. 31, but became effective on Feb. 22, bar Nigerians from receiving immigrant visas to live permanently in the United States. They can still travel to the US on temporary visas, such as those for foreign workers, tourists, and students.

But for the large Nigerian diaspora in the US, the policy could erode their deep family and cultural ties to their home country, Africa’s most populous nation and one of its economic powerhouses.

Nigerians make up by far the largest population of African immigrants living in the US, numbering about 327,000. Cities with thriving Nigerian communities will be particularly hard hit, including Dallas, Chicago, Baltimore, Atlanta, Phoenix, and Houston, the latter of which has the largest Nigerian population outside Brazil and Africa.

You might call Nigerians the ideal immigrant. Nigerians are some of the best-educated immigrants in the United States, often even ahead of other immigrant groups like Asians and Hispanics. According to U.S. Census Bureau data, about 17% of Nigerian immigrants have master’s degrees while about 4% have doctorates.

This is definitely not about “getting the best people,” as Trump likes to say of the types of immigrants he supposedly wants.

Trump’s proclamation instituting the expanded ban says that Nigeria fails to meet the US’s security standards in two ways: it doesn’t “adequately share public-safety and terrorism-related information” and presents a “high risk, relative to other countries in the world, of terrorist travel” to the US.

It’s true that Nigeria has long been fighting homegrown terrorism. Boko Haram, one of Africa’s largest Islamic militant groups, has killed almost 38,000 people since 2011 and displaced another 2.5 million. The violence has subsided since its peak from 2014 to 2015 after the Nigerian military, backed by neighboring African countries, pushed Boko Haram into the north of the country. But the group continues to terrorize some communities in other provinces, kidnapping women and children and engaging in suicide bombings.

The situation has left many Nigerians wondering why they specifically have been targeted, when many other countries might pose similar security threats. Amaha Kassa, the executive director of African Communities Together, which advocates for African immigrants and their families, told reporters Feb. 28 that, at the group’s latest meeting in New York City, dozens of Nigerians were asking one question: “Why single us out?”

Immigrant advocates say it’s based on discriminatory motivations and that the Trump administration was already targeting Nigerian immigrants

The Trump administration has been looking to decrease immigration from Nigeria for a long time, dating back to a now-infamous meeting in the Oval Office in June 2017. Trump told his advisers at the time that Nigerians who set foot in the US would never “go back to their huts” in Africa, the New York Times reported.

His administration has been restricting Nigerian immigration in the years since, clamping down on visitor visas.

Most Nigerians come to the US with employment-based visas or B visas, which are offered to short-term visitors, including tourists, business travelers, and people seeking urgent medical care. But the Trump administration has been denying Nigerians’ applications for B visas at high rates over the last two years.

In 2018, the most recent year for which data is available, about 57% of B visa applications from Nigeria were denied, putting it among the countries with the highest denial rates. That might be because Nigerians had the highest numbers of visa overstays of any African country in 2018, as well as one of the highest rates of visa overstays of any country. The administration also increased fees for Nigerians associated with certain temporary visa applications last year, imposing a potential financial barrier.

Secretary of State Mike Pompeo, who met recently with Nigeria’s Minister of Foreign Affairs, Geoffrey Onyeama, said he’s optimistic that Nigeria will take the steps needed to remove itself from U.S. visa restrictions. However, the Secretary did not offer a timeline for their removal.