- Immigrants (or just illegal immigrants?) are more likely to commit crimes.
- Stricter immigration laws would prevent more immigrants from entering America.
- Therefore, in the interests of reducing crime, we should have strict immigration laws.
First, is it true that immigrants are more likely to commit crimes? For legal immigrants, we know the answer is no, simply by counting the number of immigrants and their incarceration rate relative to native-born Americans (link). Also, there is a consistent correlation between crime and cities that get the largest waves of immigrants - crime decreases with more immigration compared to cities with less immigration (link).
Most of the examples people use of immigrants whose crime rates are perceived to be extremely high are Mexicans, so what about them? In general, crime rates among Mexican-Americans are similar to those of white Americans, and what I found surprising was that among Mexican-Americans, those who immigrate here are less likely to commit crimes than those who were born here (link).
What about specifically illegal immigrants? We can't really be sure of that simply because we can't be sure how many illegal immigrants are here in the first place. Estimates range from 7-20 million, so even if we knew exactly how many illegal immigrants committed crimes, the crimes rates could vary a whole lot depending on what the real number of illegal immigrants is. For clues, we can simply look at the crime rates for immigrants in general that I mentioned above, since illegal immigrants would count toward those totals. But in some southern states, there is some evidence that crime from illegal immigrants is higher than average, such as this estimate from the Arizona Department Of Corrections. If that's true, why would that be? It can't be due to the culture or "nature" of latino people who come here, or else we would see the exact opposite of the crime trends among different generations of Mexican-American immigrants that I linked earlier. The most likely explanation would be the drug trade, which drives a lot of the illegal crossings on our southern border.
Now, if that is true, does it justify tighter immigration laws? I don't understand how it would. If we have an increase in crime due to our drug policy that suggests we should do something about... our drug policy. We also had an increase in organized crime among Italian-Americans during the Prohibition because of the black market for alcohol. It would be silly to suggest the solution should have been to get rid of Italians.
Also consider that there are other factors that correlate more definitively and strongly with crime rates. Crime rates are higher among impoverished African Americans. They are also higher among southerners, regardless of race and social status, than they are among northerners. Not being married is also correlated with higher crime rates, as is alcohol consumption. But the most relevant indicator of one's likelihood to commit crimes is whether they are a young male. So if we're going to discriminate against a group of people simply because their crime rates are higher than those outside that group, young males takes the cake.
So... should we update our immigration laws to simply not accept young men but accept anyone else? Or should our government discriminate against American-born young males and closely track their activity for a certain age range? Should northern states pass a law preventing/limiting southerners from visiting or moving there? Those hypothetical laws follow the logic against immigration-due-to-crime much better than anti-immigration laws do. Remember that tight immigration laws are a huge Big Government infringement on liberty and the free market. Telling people where they can go/work and employers who they can hire based on something as arbitrary as the location of their birth has a far bigger impact on people's freedom than background checks and other gun regulations that much of the anti-immigration advocates decried as tyranny.
And on top of all of this, the proposed immigration reform bill in Congress puts more money into border patrol, uses things like e-verify to keep businesses from hiring illegal immigrants, and makes it easier to immigrate here legally. Those things would be expected to reduce illegal immigration, right?