Immigration arrests have soared under President Trump. Who is being swept up in the raids? Here's everything you need to know:

What's changed?

President Trump has given federal agents free rein to aggressively enforce the nation's immigration laws. The Obama administration deported 2.7 million people over eight years, but focused on undocumented immigrants convicted of serious crimes and recent immigrants caught at the border, while mostly ignoring undocumented immigrants already living peacefully in the U.S. Trump has done away with such distinctions. Within five days of taking office, Trump signed an executive order instructing government agencies to target for removal anyone who has committed a "chargeable criminal offense," including entering the U.S. illegally. Then–Homeland Security Secretary John Kelly followed up with a memo stating that his agency would "no longer exempt classes or categories of removable aliens." Immigrations and Customs Enforcement (ICE) agents made 75,045 arrests during the first half of this year, up 40 percent from 2016. "If you're in this country illegally, and you committed a crime by entering this country, you should be uncomfortable," acting ICE Director Tom Homan told Congress in a hearing. "You should look over your shoulder."

Who's being arrested?

ICE agents still target known criminals in their raids on workplaces and homes, but are now arresting any undocumented immigrants they encounter in those raids. During a series of July raids, in which ICE arrested 650 people, 70 percent weren't targets of the raid, but were simply in the wrong place at the wrong time. ICE is also going after "low-hanging fruit," undocumented immigrants known to agents. This includes the 1.8 million undocumented immigrants who have been granted a stay of deportation for medical or family reasons provided they show up for semiannual check-ins with ICE agents. Some of them are now being arrested at their check-ins. In one widely publicized case, Guadalupe García de Rayos of Phoenix, a mother of two U.S.-born children who has lived in the U.S. for more than 20 years, was detained at her annual check-in and deported to Mexico the next morning.

How are immigrants responding?

There's widespread fear in immigrant communities, with many going deeper underground to avoid the possibility of getting caught up in ICE's web. "We're terrified of being separated," said Nathaly Uribe, a 22-year-old DACA recipient whose parents are undocumented. "We live in daily anxiety and terror of being deported." At one high school in Durham, North Carolina, enrollment dropped 20 percent after a student from Honduras was arrested on his way to school. It's still against ICE policy to raid "sensitive locations" such as schools and hospitals, but emboldened agents are pushing the envelope. In one case, Border Patrol agents arrested a 10-year-old girl while she was in an ambulance on the way to the hospital to receive emergency surgery related to her cerebral palsy, with armed guards placed outside her hospital room. "They spent so much time and resources to follow this girl, to treat her like she was the highest-priority criminal that ever walked on this Earth," said Priscilla Martinez, an immigration activist.

What's the justification for that?

Immigration agents say they're just following the law. Lawmakers "should have the courage and skill to change the laws" if they don't like what they require, Kelly said in April. "Otherwise they should shut up and support the men and women on the front lines." Many immigration agents feel "unshackled," according to several news stories, with the unions representing ICE and the Border Patrol reporting soaring morale now that the federal government isn't micromanaging whom they arrest.

Is Trump's strategy working?

That depends on the goal. The pace of illegal immigration to the U.S. has slowed dramatically, at least partly because of the perception that this administration is serious about deporting those who are caught. But while arrests are up, the U.S. is actually on pace to deport fewer people this year than under the last year of Obama's presidency. The surge of arrests has badly overloaded the already strained immigration courts, which now face a staggering backlog of 630,000 cases. The Trump administration is making a push to hire more immigration judges, but it could be years before many of those awaiting a hearing exhaust all of their appeals.

Does ICE's campaign face other obstacles?

Yes, at the state and local level. At least 15 states have taken up sanctuary legislation this year, which would limit local authorities' cooperation with federal immigration agents. California has gone the furthest, formally declaring itself a "sanctuary state." That means state and local agencies will not comply with requests from ICE agents to hold undocumented prisoners until they can be arrested, or notify them about when they will be released. At least 142 jurisdictions nationwide have refused such requests, according to ICE. This is significant, because an estimated 65 percent of all deportations result from cooperation between state and local law enforcement and federal immigration agents. Trump has moved to cut off federal law enforcement funds for sanctuary cities, but his executive order was recently blocked by a federal district judge. In the end, that contest of policy and wills may be decided by the U.S. Supreme Court.

The cost of deportation

Right now, the government only has the resources to deport about 400,000 people per year, but there are more than 11 million illegal immigrants currently living in the U.S. The conservative-leaning American Action Forum estimates that it would take 20 years for ICE to remove every undocumented immigrant at its current maximum capacity, at a cost of between $100 billion and $300 billion. Those costs include apprehension, legal processing, housing, and transportation. For example, in 2014 it cost an average of $5,633 to hold one deportee in a federal detention center, with an average stay of 31 days. "You have to pay to monitor them around the clock, you have to pay to feed them every single day, you have to tend to their other needs," said David Bier, an immigration policy analyst with the Cato Institute. "The only thing that comes close is the costs of actually hiring the agents to do the arrests."