Daniel Bier has a nice rundown on the ratio of police to prison spending comparing the United States to Europe. The US spends less on police and more on prisons than any European country.
Moreover, this is not because Europe spends less on criminal justice. Surprisingly, there is very little correlation between total spending and the ratio of police to prison spending. What we see in the graph below, for example, is that Europe is on the right, indicating more police to prison spending but not noticeably below the US states on total spending as a percent of GDP.
As I have argued before, the United States is underpoliced and overprisoned.