As part of a crackdown pushed by President Trump, immigration authorities are slated to carry out a series of roundups targeting undocumented families on Sunday, according to two administration officials.

The raids — which the president first telegraphed last month only to postpone them — have left undocumented immigrants on edge, fearing they will be deported and separated from their families. As top Democrats urge Mr. Trump to scrap the operation, immigrant advocacy groups have been preparing immigrants who could potentially be targeted by Immigration and Customs Enforcement (ICE).

Who will be targeted and why?

Although the president and other officials have claimed that "millions" would be deported, such an operation would be logistically impossible and politically untenable. There are currently approximately 10.5 million undocumented immigrants living in the U.S. and according to administration officials, about 1 million of them have final removal orders.

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But the wave of sweeps that are set to start on Sunday is expected to be limited in scope, targeting about 2,000 people.

The operation is set to target undocumented families in an expedited docket in the immigration court system. According to ICE, these immigrants were ordered deported by a judge for failing to appear in court, also received notification from the agency.

ICE says very few of these people responded to the agency's request to arrange their deportation earlier this year. The group in this "rocket" docket is estimated to include about 2,100 people.

But it is highly unlikely that ICE find all of the migrants at the addresses they have on file, especially since the operation has been so publicized. Advocates fear the agency will turn to "collateral arrests," which frequently occur during "targeted" operations. These are apprehensions of people who are undocumented but who are not directly targeted by an ICE operation. They just happened to be in the place where the operation takes place.

Have these people been given "due process"?

The administration has repeatedly said the migrants that would be targeted by the operation already enjoyed due process in the immigration court system. Officials have also accused these individuals of ignoring U.S. laws for a second time by not showing up to court.

But immigration attorneys and advocates dispute that. They said migrants may have not known about their court date.

"It's quite possible some of the families that have been ordered removed did have due process, did have a hearing and were ordered removed — and then failed to report for that removal order," Aaron Reichlin-Melnick, a policy analyst at the American Immigration Council, told CBS News. "But the vast majority of people were ordered removed for missing court. And it's quite likely that many of those individuals missed court through no fault of their own."

"By definition, a person can't have had their day in court if they never knew they had a day in court in the first place," he said.

Reichlin-Melnick said many people did not receive a notice to appear in court because these are often sent to the wrong addresses, with erroneous dates or different locations and other bureaucratic errors.

Advocates and attorneys also noted that some immigrants do not appear in court because of a lack of legal representation. Immigrants and migrants in the U.S. immigration court system — which is a branch of the Justice Department — do not have the right to a government-appointed lawyer, unlike the independent judicial system. It is up to advocacy groups to fill that void.

"There's no right to counsel. And study after study has shown the appearance rate of people who have a lawyer is significantly higher than those who don't have a lawyer," Reichlin-Melnick said. "Unfortunately immigration court is a very complex system — far more complicated than many other courts — and without a lawyer to navigate the system, the individuals who intend to follow the rules simply aren't able to."

People rally in Little Tokyo to oppose a Trump administration plan to use Fort Sill Army base in Oklahoma as a detention center for immigrant children and other detainees in Los Angeles on June 9, 2019. David Mcnew/AFP/Getty

Will families be separated because of this operation?

Deportations can lead to family separations, as they have in the past. Roundups would not only affect undocumented immigrants with pending removal orders, but also so-called "mixed-status" families with members who are green card holders and U.S. citizens — mostly U.S.-born children.

Will everyone apprehended be deported?

The removals of many of the people will likely be delayed or even halted, as advocates are preparing to file legal motions to reopen the cases of the migrants who are apprehended by ICE.

However, immigration attorneys noted that immigrants and migrants who are not able to secure counsel will face likely insurmountable odds against a government that's determined to deport them.

"For the most part, they're subject to the whims of this very dysfunctional immigration court system," Sarah Pierce, a policy analyst for the Migration Policy Institute, told CBS News.

"When you go to immigration court, you are in a very intimidating environment and subject to very complicated procedures, legal norms and terminology," Pierce added. "You're also facing a very well-trained attorney who's representing the government and who's trying to deport you."

How are advocates preparing?

From New York and Baltimore, to Houston and Los Angeles, pro-immigrant groups and legal aid organizations are mobilizing to educate their local immigrant communities. They are also trying to quell the fear already prevalent in many households.

Luba Cortés, an immigrant defense coordinator, said pro bono attorneys and advocacy organizations like Make the Road need to strike a "balancing" act: Inform without prompting mass panic.

"We don't want to create any fear or chaos as they target these immigrant families," Cortés told CBS News.

Along with providing free or low-cost legal counsel, some organizations have also established hotlines so people can report ICE activity in their neighborhoods.

Why does the government want to do this?

In June, former acting ICE director Mark Morgan, who now heads Customs and Border Protection (CBP), told reporters that the operation is designed to send a "powerful message" of deterrence to people in Central America. Morgan said his former agency wanted to uphold the values of "humanity, compassion and dignity" but that it was also critical to prevent what he portrayed as the erosion of the rule of law.

"I don't want to send ICE agents to their workplace, I don't want to send ICE agents to their homes. I don't want to send ICE agents to try to track them down and apprehend them in their communities, in their towns," he added. "That's not what I prefer to do. But we have applied due process. And we've tried to work with them. We've tried and attempted to say, 'Hey, come turn yourself in.' But they have refused to do so. So we have no choice but to carry out our statutory mandated job."

Can it be stopped?

That's unclear. The president postponed the raids last month and could do so again, particularly if he's faced with massive public uproar and opposition in Congress. There's also the possibility that litigation could block the sweeps after they begin.

The American Civil Liberties Union (ACLU) has already filed a preemptive lawsuit in the Southern District of New York, arguing that many of the people who could be targeted have not had due process. Like many attorneys, the ACLU pointed out the bureaucratic errors that often lead migrants not to appear in court.

"Even when the government sent notices to the right address for a real hearing, it repeatedly sent them too late, for locations unreasonably far from immigrants' homes," the ACLU said. "Notices thus arrived either after the date set for a hearing or just a few days before, requiring indigent families to immediately travel across the country to hearings in distant states."