From AS’ source above…
"That number comes from Rep Steve King. He got that figure from a Government Accountability Office report issued in April 2005. It read:
“At the federal level, the number of criminal aliens incarcerated increased from about 42,000 at the end of calendar year 2001 to about 49,000 at the end of calendar year 2004 — a 15 percent increase. The percentage of all federal prisoners who are criminal aliens has remained the same over the last 3 years — about 27 percent.”
So, King figured (admitting that the number would go up or down a percentage point or two):
” That means then that criminal aliens are committing 28 percent of the crimes in the United States. And so that means 28 percent of the murders, 28 percent of the rapes, 28 percent of the violence and the assaults and battery, first- and second-degree murder and also manslaughter attacks are committed by criminal aliens.”
In other words, since 28 percent of the prisoners were immigrants in the country illegally, they must also therefore have committed 28 percent of each and every crime! Quod erat demonstratum. Recognizing that this sounded like a lot even at the time, King rationalized it by asserting that for every undocumented immigrant in the country we know about, two or three sneak in without our knowing it. Here’s how we know that’s not true.
There is an almost impossibly large number of problems with King’s argument.
The first is that, of course, crime is not evenly distributed among populations. If 10 percent of prisoners are named John, that doesn’t mean that people named John commit 10 percent of murders. Many of those undocumented immigrants in federal custody were probably there for a very specific type of crime: felony immigration violations. Very, very few native-born Americans were there for that. In fact, in 2014, half of criminal arrests were for immigration violations. Since the GAO data are only for federal prisoners, that’s significant. (It’s also worth noting, as a reader did, that federal prisoners make up only a small percentage of the entire prison population.)
What’s more, the GAO data dealt with “criminal aliens” — defined in the report as “noncitizens convicted of crimes while in this country legally or illegally,” emphasis again added. In other words, King’s 28 percent number included people who weren’t even immigrants who had entered the country illegally.
Put simply, King seems to have basically made the number up more than a decade ago and, since there isn’t good data on the number of crimes committed by people who immigrated illegally, it was embraced by those looking to put a number to it. There’s simply no credible reason to believe that there have been 63,000 killings committed by undocumented immigrants since 9/11, and plenty of reason to think that the homicide rate among members of that group is lower than for native-born Americans.
What’s really remarkable, though, is that this is a bit of data that was just presented as a matter of fact by the president of the United States. This was a number so impossibly useful for Trump that when he first heard it, even he was a bit wary about its provenance. And yet, three months later, he’s presenting it as accurate without a hint of an asterisk.
In 2011, King presented a resolution that offered a different calculus.
“According to the Government Accountability Office,” it read, “there have been 25,064 homicide arrests of criminal aliens since 1955.”
That’s about 1.2 per day."