But the causal relationship between crime and poverty is only likely for some hypes of crimes. Other crimes, such as fraud, crimes of passion, serial murder etc. Bear absolutely no link to poverty. There may be even an inverse link, since poor people are not in a position to carry out a crime like fraud or insider trading. This paper lists some of the statistics that show a possible correlation between poverty and crime – mainly property crime, more than violent crime. There is also the fact that African-Americans in the U. S. Re overrepresented both in prisons and in poverty statistics (see here), indicating as well that there is a correlation. There is some anecdotal evidence (there are many sews stories indicating a link, such as the stories about people stranded on a desert island, being subject to extreme scarcity and engaging in crime such as murder and cannibalism). But there’s also anecdotal evidence to the contrary. During the Great Depression, for example, crime did not increase significantly. Poverty can also be an indirect cause of crime.
As it leads to under-education it may make the choice of a criminal lifestyle more likely. This graph shows the proportion of IIS inmates that is illiterate, compared to total US illiteracy: (source) couldn’t find any data on previous illiteracy, so it may be that under- education (and hence in many cases poverty) is not the cause of crime, but the consequence; being in prison in principle doesn’t help you to get educated. Anyway, it seems intuitively acceptable that there is some causal link between crime and poverty, in both directions.
So dealing with crime without dealing with root causes of crime such as poverty, and only focusing on punishment is indeed not the best option. However, none of this should imply: that poverty somehow determines crime, or that crime is a necessary result of poverty; many poor people are not criminals, and many rich people are that poor people are perhaps not predetermined to be criminals, but that they are more disposed to crime than other people; that would be insulting that there are no other, perhaps more important causes of crime such as irresponsibility, immorality etc. That poverty is somehow an excuse for crime, or perhaps even a justification; I think its not even a mitigating circumstance that poverty should be reduced to a problem of crime; poverty, slums and homelessness should not be eliminated because they are so-called breeding grounds of crime, but because we have a moral duty to do so. Given the causal link, we should also accept that poverty, like a bad upbringing, is often abused as a false excuse for crime.
A related question is the following: are poor inmates incarcerated because they are criminal or because they are poor and can’t escape the law as easily as the rich? Article 14 of the International Covenant on Civil and Political Rights gives everyone the right to legal defense, without charge if necessary.