You're incorrect.  The taxes addressed by Jesus were Roman taxes, an invading, occupying army for a state that gave nothing to those Jews in their homeland.

"Our" government is not an invading, occupying army for a state that gives nothing to us.  Or, it's not supposed to be, however, it does resemble such quite a bit.  "Our" government is supposed to be for "us."   Therefor, "render unto Caesar" does NOT "support" taxation, but it supports people recognizing power, even unfair worldly power, and choosing wisely.    

You gotta love those lyin' Christians who twist the bible to support their evil beliefs and actions in the world.