Kari Hong is a professor at Boston College Law School and an immigration lawyer.

President-elect Donald Trump has tried to soften his approach to immigration by saying he will focus on deporting those with criminal records. This strategy may sound sensible, but based on my experience representing noncitizens with criminal convictions, I can report that it won’t work. Instead, such an approach would be inefficient, cumbersome, expensive, unnecessary and, above all, inhumane.

First, current law fails to sort dangerous noncitizens from those who are harmless. Criminal records alone are neither an efficient nor an effective way to determine this. One of my clients — a man who had been in the United States on a green card for 40 years and whose wife and children are citizens — was deported for stealing a $2 can of beer. Another green-card holder with a citizen wife and children is fighting a deportation order issued because, two decades ago, he was convicted of petty theft, an infraction that’s less serious than a misdemeanor.

And this problem cannot be cured by focusing on those convicted of violent crime. In theory, that sounds right. But in practice, the definition of “violent” confounds federal judges and sweeps up many people whose crimes would not ordinarily be viewed that way. For seven years, until the Supreme Court finally stepped in, numerous noncitizens were deported because courts wrongfully concluded that state convictions for driving under the influence were crimes of violence. And a Virginia court in 2013 upheld an assault and battery conviction as violent even though it was committed by a teenager who spat at a police officer during his arrest.

Second, the immigration courts are already overburdened and cannot cope with a large influx of cases. No matter how many noncitizens are rounded up, each one is entitled to a hearing. This is not a mere technicality: Five in 10 of those in immigration proceedings win their cases.

Meanwhile, there is an average three-year wait before a hearing is completed. Any promise to start rounding up criminal aliens or undocumented people, without money, without judges and without courthouses, is illusory. The current backlog is about 500,000 cases; just imagine what would happen if that number increased by just 1 million, let alone 3 million.

Third, as a fiscal matter, it is expensive to lock people up while they wait for these immigration hearings. Currently, more than 30,000 people are detained daily at an annual cost of more than $2 billion — an expense that is difficult to justify given that half of them may be entitled to remain.

Fourth, stepping up deportation in the way Trump envisions is unnecessary. The southern border is the most secure it has ever been. Despite the rhetoric that hordes of immigrants are sneaking across the border from Mexico with nefarious plans to bring crime, violence and drugs into the United States, the fact is that noncitizens commit fewer crimes than citizens.

In addition, the deportation process works, as evidenced by the Obama administration having deported more than 2.5 million people over eight years — more than the combined presidential administrations of the 20th century.

(Jayne W. Orenstein and Osman Malik/The Washington Post)

Fifth, there are not 3 million undocumented people with criminal convictions; the Migration Policy Institute places the number at 820,000. The call to deport criminal aliens portends a crackdown on noncitizens with green cards that allow them to live and work here legally, but who have run afoul of the law for reasons ranging from serious felonies to minor crimes, including drug possession and misdemeanors. Such people often have served in our military, have children and spouses who are citizens, have lengthy employment histories, pay taxes and are good neighbors. We — as Americans — have a stake in keeping those immigrants here. Kicking them out and disrupting their families over minor offenses would be harsh and absurd.

If Trump truly wants to focus on drug dealers, terrorists, murderers and rapists, he should call on Congress to restore immigration law’s focus on those whom prosecutors and criminal judges determined were dangerous in the first place — people who were sentenced to five years or more in prison. That’s what the law used to be, before it was changed in 1996 to cover many more crimes.

Instead of penalizing immigrants for minor crimes, immigration law needs to separate contributing immigrants from their non-contributing peers. Those who pay taxes, have children born in the United States, serve in the military, work in jobs American citizens will not take or help those around them need a path to legalization. Those who cause more harm than good should be deported. Restoring proportionality and common sense to immigration law would certainly help make America great again.