Does our taxes paid to the government used for entitlements qualify as part of our tithing?

George, interesting question.   I would say that it does not equate to paying tithes since it is involuntary (taxes), and it is paying for services as much as helping the poor.   In otherwords, old age security is available to most people, and unemployment benefits are paid from wages, based on the assumption that if you are unemployed, then you can access it.  It is more insurance than donation.  While it is true that some of the church's tasks of helping the poor have been reduced or made easier by the fact that the state has put in place methods for assisting the poor, you could argue that simply providing for your family from your wages also prevents poverty in your wife and children, and thus does the same thing.   When the church helps the poor it comes with the message that we do this because Jesus loves us.   When the state does it, it is usually to prevent disgrace or food riots. 

Should paying secular bureaucrats to fund and administer government programs count as a tithe because some of those programs help poor people?  No, of course not.

But does the fact that most Americans are required at gunpoint to pay close to (if not more than) half their income in taxes (federal income, state income, property, sales, gas, etc.)  to the government make it MUCH, MUCH harder to tithe?  Of course it does.

There is something to be debated about whether tithing should be on one's gross income or net income. I suspect that tithing by the people of Israel also went for some administrative purposes, possible even the maintenance of the King and his palaces. But I would love to be informed by someone who knows better. So even then, the tithe was something like a tax. Some portion of current taxes are for doing good, but most go to support the core functions of the state -- defense and administration of justice (in my ideal world, at least.) As for the taxes that come directly out of my pocket, namely the property, sales, and gas taxes, I have a little bit of control over those, buy controlling what and how much I buy, while admitting that I am relatively powerless to set the tax rates on those.

Clearly, in the New Testament, Christ wants us to give generously, and a tithe is a good starting place. But I would calculate my tithe on the money that shows up in my bank accounts (or similar pockets). That is the part I have some control over, the part that I see as given to me by God to administer on his behalf.