A report issued by the liberal Migration Policy Institute (MPI) further shreds Chuck Todd’s assertion on NBC’s “Meet The Press” last Sunday that he and his staff, “couldn’t find a single study that links violent crime and immigration.”

Tucked inside a report about President Obama’s new amnesty is the estimation from this liberal think tank there are 820,000 illegal aliens in the United States with criminal convictions, including 690,000 illegal aliens currently residing on U.S. soil who have been convicted of a felony or “serious” misdemeanor.

The 820,000 figure is not an estimation of total crimes committed by illegal immigrants—which would be a much higher number—but only those illegal aliens successfully identified, arrested, tried, and convicted.

Combined with other statistical data points, however, the 820,000 figure gives us a way to examine the scope of total illegal alien crime. Even conservative assumptions produce harrowing conclusions, and demonstrate that there are likely millions of American victims of illegal alien predators.

First, the appendix in MPI’s report explains that it reached the 820,000 figure by “assuming unauthorized immigrants and lawful noncitizen immigrants commit crimes at the same rates.” While millions of Americans have been victimized by aliens with visas—the U.S. issues the majority of its visas to either unstable, poor, or violent countries.

MPI’s assumption is still overly-generous. The mere fact that illegal aliens are more likely to be young and male than aliens in general makes the assumption flawed. The true population of criminally-convicted illegals is almost certainly quite a bit higher.

But this still provides only a fractional snapshot of the total population of criminal illegal aliens. MPI’s estimation covers only those individuals caught, arrested, tried and convicted. But millions of crimes are committed that never result in a conviction.

For instance, less than half (48.9 percent) of violent felony arrests in New York City result in a conviction and sentence, according to a report from the New York State Division of Criminal Justice Services. The national “clearance rate” for homicides is 64.1 percent—meaning less than 2 in 3 murder cases results in the suspect even being arrested, let alone convicted. In Washington D.C., according to police data analyzed by The Washington Post, only 1 in 3 homicides results in a conviction.

What this means is that for the hundreds of thousands of illegal aliens who have been found, caught, tried, and convicted, there are hundreds of thousands more illegal alien offenders on the loose who have never been successfully identified or convicted. This latter point is also important because it is the policy of the administration and Sanctuary Cities to free criminal aliens if convictions aren’t obtained—giving them ample opportunity to continued their crime spree. Of course, tens of thousands with convictions are freed as well.

The task of getting a conviction has only grown more difficult over time. As The Washington Times reports, “The national homicide “clearance rate” — that is, local police identifying and arresting killers — has slipped to 64.1 percent from more than 90 percent just 50 years ago.” The Washington Times explains that this marked decline is attributable in part to “higher closure standards and more crimes being committed by gangs and drug dealers who may have no local footprint and/or encourage ‘no snitch’ mentality.”

The liberal-leaning National Public Radio explains that this is especially true for crimes committed in communities likely impacted by immigration: “Since at least the 1980s, police have complained about a growing ‘no snitch’ culture, especially in minority communities. They say the reluctance of potential witnesses makes it hard to identify suspects.”

Low crime-to-conviction rates in general are likely greatly exaggerated for certain crimes committed by immigrants and especially illegal immigrants. Illegal lawbreakers not only have an extra incentive to flee to avoid trial in order to avoid deportation if convicted, but also can more easily do so. It stands to reason that a citizen charged with breaking into a car is less likely to flee the country than an illegal alien charged with the same. Many illegals also flee immediately, long before anyone comes looking for them.

As acclaimed Manhattan Institute scholar Heather Mac Donald has documented, “In Los Angeles, 95 percent of all outstanding warrants for homicide (which total 1,200 to 1,500) target illegal aliens. Up to two-thirds of all fugitive felony warrants (17,000) are for illegal aliens.”

This suggests that the enormous number of convictions for illegal aliens only points to a vastly larger number of alien criminals who evaded conviction any one of ways including fleeing the jurisdiction, fleeing the country or being shielded by large transnational gangs like MS-13.

Most Wanted Lists across the country point to the number of extremely violent and serious crimes where the immigrant perpetrator is at large. Moreover, the number of crimes per criminal is greater than 1. For instance, GAO found an average of 7 arrests per incarcerated alien. All told, this means there are certainly millions of Americans who are the victims of criminal acts by illegal aliens. Each and every one of these crimes could have been prevented had our laws been enforced.

Some federal lawmakers, however, have moved to eliminate those laws altogether. Under the Gang of Eight plan, introduced by Senators Rubio and Schumer, large numbers of criminal aliens would be made into U.S. citizens. As ICE Council President Chris Crane explained:

Senator Rubio left unchanged legislative provisions that he himself admitted to us in private were detrimental, flawed and must be changed. Legislation written behind closed doors by handpicked special interest groups which put their political agendas and financial gains before sound and effective law and the welfare and safety of the American public. As a result, the 1,200 page substitute bill before the Senate will provide instant legalization and a path to citizenship to gang members and other dangerous criminal aliens, and handcuff ICE officers from enforcing immigration laws in the future. It provides no means of effectively enforcing visa overstays which account for almost half of the nation’s illegal immigration crisis.

The Gang of Eight bill would also have tripled the number of green cards given to mostly poor immigrants from around the world, including the Middle East.

The tally of illegal immigrant crime does not measure the total number of crimes committed by immigrants. There are an additional 30-plus million immigrants in the country with visas, green cards or naturalization papers. These immigrants mostly arrived as part of the Ted Kennedy-backed 1965 immigration law, which offered up tens of millions of American visas to people from the world’s poorest and least developed nations. Crimes committed by individuals with a Kennedy-created visa would be in addition to crimes committed by immigrants without visas. The top countries of origin for both aliens with visas and aliens without visas tend to be the same.

For instance, the Islamic terrorist who murdered the Marines in Chattanooga was here as part of this ever-increasing production of visas: Mohammad Abdulazeez was given a visa to come to the United States and then later handed citizenship documents before slaying five heroes in cold blood.

Finally, as Heather MacDonald observed, the children of immigrants commit crimes at higher rates: “between the foreign-born generation and their American children, the incarceration rate of Mexican-Americans jumps more than eightfold” causing her to observe: “unless we can prevent immigrants from having children, a high level of immigration translates to increased levels of crime.”