This is less of a legal question and more of a moral one. I'll just say that, in the Bible, when asked a somewhat similar question, Jesus said, "Render to Caesar the things that are Caesar's, and to God the things that are God's." This did not mean Jesus condoned everything the Roman government was doing. Quite the opposite. But it does illustrate an important point:
Governments are not single human beings; they are run by many, many different people, who will not always govern the same way. Some of those individuals are better than others. Some are worse than others. By the time a given tax dollar (or denarius) is filtered all the way down to a corrupt official's pockets, and by the time it is used to the end of corruption, the responsibility lies with the corrupt official(s), not with the taxpayer.
There are a lot of good things that come from governments, as well as evil. Generally speaking, the evil that is performed by a government is not a central tenet of the purpose of that government's existence, and it is simply one or more individuals mishandling things on their own. Granted, certain issues will be systemically rampant within a given government, but are they still blemishes on the design, not part of the design itself. (There are exceptions, but the US government is not on that level.) And much of a given tax dollar will also fund the good that a government is doing. In the end, when somebody uses a government's treasury in an act of corruption, that is (generally) their responsibility, not the taxpayer's.
Once again, yours is less of a legal question and more of a moral one.