The 2013 Schumer-Rubio Amnesty/ Immigration Surge bill now being debated aims to double legal immigration from what are already historic highs. In many ways, it can be regarded as the 1965 Immigration Act on steroids.

The 1965 Act notoriously unleashed an era of mass immigration after a 40-year lull, and shifted the ethnic mix of new immigrants from predominantly European to Hispanic and Asian. It is responsible for setting the US on the path to a white minority by 2040 or so. In future columns, I’ll be looking at its consequences in several other areas. Today: crime.

Crime rates have been falling for some two decades, while the foreign-born share of the U.S. population has been increasing. Immigration enthusiasts regularly tout this coincidence, but they are being intellectually dishonest. They simply don’t look back far enough.

A historic crime wave accompanied the post-1965 era of mass immigration. To this day, violent crime rates have not returned to the levels of the early 1960s.

The national crime rate—violent crimes per 100,000 population—rose from 200.2 in 1965 to a peak of 758.2 in 1991, according to historical FBI crime data. That was an increase of 279%. It’s now back down to 403.6.

Over the same period, California’s violent crime rate exploded by 356%. In New York State, the violent crime rate peaked in at 1,180.9 per 100,000 population in 1990, or nearly 62% above the national rate that year. It can hardly be a coincidence that California and New York were the epicenters of mass immigration in the decades following 1965.

We are not arguing that immigration was the only reason crime surged, but it certainly played a role. Similarly, crime has declined after 1990 for many reasons, including tougher enforcement—but immigration has played a role in retarding that decline.

Typical of the utterly irresponsible attitude of all levels of American government to the post 1965 immigrant influx, there has been no systematic effort to collect data on foreign-born crime.

Lacking good info on prisoner nativity, we can still get a sense of the role immigration plays by comparing the crime rates for Hispanics, non-Hispanic blacks, and non-Hispanic whites. Hispanics are about 36% immigrant (and nearly one-third of native-born Hispanics are less than 25 years old, many of them children of recent immigrants).

Unfortunately the FBI’s Uniform Crime Report database does not separate Hispanics from other racial groups. Hispanic arrestees are reported as “white”, ”black”, or even “Asian”—rendering the crime data useless for our purpose.

In fact, most Hispanic perpetrators are lumped in with non-Hispanic whites. This has the effect of narrowing the gap between black and white crime rates, by inflating the white rate, while suppressing information on Hispanic criminality. It is hard to avoid the conclusion that Justice Department bureaucrats are too PC to present the truth on immigrant, primarily Hispanic, criminality.

Luckily, the folks that prepare the incarceration statistics didn’t get the memo. Their data carefully records ethnicity (Hispanic/non-Hispanic) as well as race of the prison population. Accordingly, my go-to source for ethnic crime statistics is the Bureau of Justice Statistics’ annual year-end survey of prisoners held in state and federal lock-ups.

To avoid charges that we are stacking the deck against Hispanics, we focus solely on prisoners held in state facilities, thereby excluding individuals sentenced for violating Federal immigration laws.

The role of immigration on violent crime committed in the U.S. remains all too clear:

From 2006 to 2010 the number of white prisoners doing time for violent crimes fell 1.0%, the number of blacks rose 5.3%, and the number of Hispanics jumped 22.3%. Hispanics accounted for about 95% of the increase in prisoners sentenced for violent crimes over this period.

By comparison, only 16.3% of the U.S. population was Hispanic in 2010.

The Hispanic role in murders is larger still:

The number of prisoners doing time for murder declined 1.1% from 2006 to 2010. White prisoners fell by 7.8%, Blacks rose a mere 0.3%, and the number of Hispanic prisoners rose a whopping 19.7%.

Inescapable conclusion #1:

Had national crime rates fallen to 1965 levels, there would have been 628,100 fewer violent crimes committed in the U.S. in 2010—a reduction of 50.4%.

Inescapable conclusion #2:

Immigrants, and their U.S.-born children, have prevented violent crime from falling as far as it otherwise would have done since 1990.

Edwin S. Rubenstein (email him) is President of ESR Research Economic Consultants in Indiana