Last week, about 70 groups representing civil rights advocates, minorities, labor and the arts signed an open letter in protest of the new law. At least two rights groups are preparing to fight the law in the Constitutional Court, the nation’s highest court for constitutional matters.
The law was first presented by Belgium’s secretary for asylum and migration, Theo Francken, a Flemish nationalist and a member of the center-right government, in July in the wake of the Brussels terrorist attacks that killed 32 people and wounded 340.
On Feb. 9, Mr. Francken managed to slip an amendment to the country’s Foreigners Law before Parliament without much of a public debate, let alone opposition. Although the law was discussed in a parliamentary committee and during a plenary session, most real discussion was limited to closed-door cabinet meetings, experts said.
Since then, Mr. Francken has been increasingly on the defensive over the measure.
“I am not going to put someone out of the country, who has lived here all of his life and has children here and so forth, just because he got two speeding tickets. That’s absurd,” Mr. Francken said in a telephone interview. “That is not my intention at all.”
“Let me be very clear. This is about 20 cases of terrorism and 50 cases of heavy criminality,” he said. “It’s about simplifying the procedures of orders for leaving the territory.”
But a month after the law passed, some members of Parliament and civil society groups are growing worried about the powers that it granted to the executive branch.
“We’re turning the clock back 10 years,” said Jos Vander Velpen, president of the Belgian Human Rights League. “We have six months to appeal it, and we’re already intensively preparing our arguments.”
In particular, the report warned that a 2015 law allowing the authorities to revoke Belgian citizenship from dual nationals convicted of terrorism could create perceptions of a tier of “second class” citizens based on their ethnicity and religion.
“Belgium has worked hard this past year to prevent further attacks, but its law and policy responses have been undermined by their overbroad and sometimes abusive nature,” said Letta Tayler, a senior terrorism researcher at Human Rights Watch and the report’s author.
Belgium, a country of 11 million people, received 107,000 requests for asylum over the last four years and granted it in over half of cases. During the same period, Belgium became the biggest per-capita exporter of foreign terrorist fighters in Western Europe — about 500 joined the Islamic State in Syria.
The country also served as a base for most of the terrorists who carried out the attacks in Paris in November 2015 and in Brussels in March 2016. All of them had immigrant backgrounds, and only some were Belgian nationals.
The new law asks officials to weigh the possible threat a foreigner poses against the links that person has with Belgian society. It will be tougher to expel someone with strong links, who has a family and a job, but easier to do so with someone who barely visits the country.
In its previous form, the Foreigners Law, which dates to 1980, allowed the deportation of foreigners only after they were convicted of serious crimes, including terrorism, and with the oversight of a magistrate. People who were born in Belgium or moved there under the age of 12 were exempt from deportation.
All of those restrictions have been eliminated.
An amendment in 2005 built in most of these protections, “the result of a decades-long battle,” said Mr. Vander Velpen, the human rights lawyer.
His organization is building a case against the new law, based on the argument that it violates the separation of powers and denies a foreign resident the right to appeal.
“The Immigration Office can immediately, without interference of a judge, put someone out of the country based on indications that he or she could pose a threat to the public order,” he said.
Afterward, that person can appeal the administration’s decision in front of a judge, but that does not suspend the immediate deportation, Mr. Vander Velpen explained.
Government officials have offered assurances that there are exceptions in case of extraordinary emergencies — when deportation poses an imminent danger to a person’s life, for example.
People representing groups that defend the interests of minorities said they worried that the law would deepen the divide between residents who hold a Belgian passport and those who don’t. They fear the law gives the Immigration Office too much power to arbitrarily interpret the meaning of “public order” and “national security.”
Those who might be affected have been vocal in their opposition. They include Belgium’s 1.3 million legal residents who do not have Belgian nationality — some 10 percent of the total population, according to government statistics.
Aya Sabi, a 21-year-old columnist for two Belgian newspapers, sent Mr. Francken a Twitter message last month saying that as a Dutch national with Moroccan ancestry living in Belgium for eight years, she had become deportable “since recently.”
A heated and public exchange ensued, with Mr. Francken accusing her of lying and trying to draw attention to herself.
“You’ve always been deportable,” he responded. “By the law voted by the left in 2005. Why didn’t I hear from you back then?”
Ms. Sabi replied that in 2005 she was 10 years old.
In an interview this month, she said that “removing terrorists from Belgian soil isn’t going to solve anything; they’ll just continue abroad.”
“That’s the same logic the government applied when foreign terrorist fighters started to leave for Syria,” she added, “and that didn’t turn out well, did it?”
Confronted with the argument, Mr. Francken said the new law lets him withdraw the Belgian residency permits of about 20 fighters in Syria who are about to return. He will move to do so on the first day the law takes effect, which is in about 10 days, he said.
“If I can keep a Syria fighter in Syria, then I’ll definitely do that, that’s for sure,” he said. “We’re already taking back all the Belgian nationals. And to be honest, we don’t know what to do with them anymore, and in fact, the whole of Europe doesn’t know what to do with these people anymore.”