Stopping Christianity is not required. It will destroy itself like all other bad ideas. First ask yourself, why has it lasted so long? Christianity got its start in the 4th century when it was institutionalized by the Roman Empire. Before Nicaea, it was gaining popularity among ignorant, uneducated small groups living in the outlying areas of a declining empire. Canon was very carefully scripted, edited, and chosen to match up with the Septuagint in the mid second century probably by Gnostics. The various early Christian cults had concocted various "gospels" and lived by various doctrines such as Gnosticism and, Docetism. These cults were in competition with each other to have their version of Christianity proselytized to new converts. Constantine merely saw institutionalizing it as a means of consolidating control of the people. The church then gained a stranglehold on every aspect of life in Europe from that point onward. It had complete control of all communication up until the Protestant reformation. Even then, challenging Christianity could prove fatal as all dissent was crush by all denominations. Things started to change with the enlightenment and the colonization of the new world. However, it wouldn't be until the eighteenth century that men could start talking freely about matters of religion without fear of death. Yes, I'm long winded but, the subject matter deserves serious attention. To sum up the answer to the question: Christianity has relied on ignorance and coercion to remain relevant.

Enter the information age. Knowledge is the enemy of religion. It is dying before your very eyes and, there is nothing you can do about it. It is comical to watch theists flail helplessly in the sea of their stupidity and spurious claims on the internet. Most people in Europe are nonbelievers and, the US will catch up not by what atheist say but, rather, by what theists are saying. People are waking up and are getting sick of the false hope and empty promises. Not to mention, they are starting to see the money game as well. Just look at where you and I are standing. I'm standing on dry land and, your standing on a sinking ship out at sea. Just think, you will cease to be a Christian when you die and, who will replace you?

If you lived in a small town and your house and the local church were on fire. Whose house do you think they would put out first?

They should be paying income tax like any corporation or individual IF they choose to engage in the politics of the land. I'm pretty sure that staying out of political matters is a stipulation of the justification for tax exempt status to begin with. It has to do with the Jeffersonian concept of separation of church and state. I know for a fact that the Catholic Church actively engages in politics as I have participated in the Catholic lobby in Albany, NY. How have religions obtained tax exempt status? Here is the IRS version of the story: http://www.irs.gov/pub/irs-soi/tehistory.pdf.