How the Current Immigration System Goes After Criminal Noncitizens

— -- Donald Trump's long list of policy proposals to curb illegal immigration includes several initiatives that are already in place or have already tried and failed, experts say.

Trump wants to triple the size of one of the main government bodies that deals with locating undocumented immigrants, and, once found, wants any offenders who commit any kind of crime to "be placed into immediate removal proceedings," he said in his immigration speech on Wednesday.

How It Works Now

One of the areas that Trump sees room for improvement is in the operation of the U.S. Immigration and Customs Enforcement (ICE), which Trump wants to triple in size.

John Cohen, a former Department of Homeland Security acting undersecretary who is now an ABC News consultant, said that the agency is doing the best it can and is dividing up the workload accordingly.

"Recognizing that there is limited amount of resources, government officials chose to focus on those who are in the county illegally that are either dangerous criminals such as gang members or that represent a national security threat and focus ICE's deportation and removal investigations and deportation efforts on that population," Cohen said.

Cohen said it could take up to two years to get ICE agents, after they have passed background checks and interviews, to be trained to the level that would be needed to do the immigration work at hand.

As it stands, ICE works with Customs and Border Patrol and the Department of Homeland Security and their focus on immigration is broken down into three major areas.

The first, Cohen said, is focusing on vetting potential visa overstays and then determining whether any of those are "public safety or national security threats."

The second is their work with state and local law enforcement groups that specifically target violent criminals.

The third step is identifying when someone who is here illegally has been arrested, and determining whether they should be put through the deportation process.

"No one disagrees ... that ICE and Border Patrol and other authorities should do everything they can to prevent the entry of violent criminals," Cohen said. "Where you get disagreement even within the law enforcement community is in determining what should be the role of law enforcement when it comes to removing people who are not violent criminals."

Picking the Targets

Cohen said that ICE and the various agencies have been focusing on targeting those noncitizens who are public safety or national security threats first — which is a plan that Trump has reiterated.

The Priority Enforcement Program, the law which is currently in place, breaks down various crimes into different priority levels, putting those posing "threats to national security, border security and public safety" at the top level, those who have misdemeanors in the second level and anyone who arrived in the country after Jan. 1, 2014, in the third level.

In 2015, 81 percent, or 113,385, of the removals were the priority one removals.

Kari Hong, an assistant professor at Boston College Law School who founded a clinic that represents noncitizens with criminal convictions, said that she and other activists believe that the current system unjustly lumps different crimes together, meaning that some people with less serious crimes technically fall into the higher priority categories.

"The scheme is unduly harsh," she said. "My concern, what I've been seeing in my practice, is that you're sweeping in way too many people."

"Every single study shows that immigrants commit fewer crimes than the native-born population and they reoffend at significantly lower rates than the native born," she said.

She said that Trump's inclusion of the Angel Moms, a group of parents who lost their children or spouses to crimes committed by noncitizens, at his rally in Phoenix on Wednesday was part of a "cynical" take on the issue.

"I'm saddened obviously for those families who have lost people but his highlighting those crimes is a complete distortion of the issue and a very cynical distortion of the issue," she said.