Actually, there is some stuff in the constitution about income tax. But it wasn't added until last century.
RE: Tax, (not religion) we do not tax the wealthy at a higher rate. The highest tax rates, and the alternative minimum tax, kick in well before the level that anyone could be considered wealthy. And, considering that the SSI caps out at about 70 grand, we actually tax those folks that make more at a lower rate. Now, allegeldy, the wealthy pay more in tax in this country, and that is because they make more. Arguably, they'd pay more under a flate rate (but not a flat tax) because they'd be taxed at the same rate on more dollars.
Historically, we had a much higher, and much more graduated tax in this country. At the time, there were some moral dilemnas attached to making too much money. That seems to have disappeared. What has happened is that the highest tax rates have been decreased and the tax burden has been shifted to the middle class.
Now, even under our current situation, the wealthy are not taxed at a higher rate than poor folks. With certain exceptions, ANYBODY, whether they make 20 grand or 80 or 120 or more has the benefit of the lower tax rates for the first dollars earned. AND anybody that makes more and passes the threshold to the higher rates is taxed at those rates on the dollars above the threshold.
The philosophy behind this (Besides just earning votes) is that people who don't make much money need all that they have to survive on. Taxing someone who makes a 1k a year at a 30% tax bracket is a lot heavier hit than taxing someone who makes 100k a year. Don't tell me that I work harder just because I make more than someone who has two full time minimum wage jobs. They earn every penny and should be entitled to a better life for it. However, if you haven't done the math lately, someone who has a two kids, and works two minimum wage jobs full time (80 hours a week) is still well below the poverty level. I don't want to be taking food out of their mouths to lighten my tax burden by a few dollars.
ON another point. Belief in God is not some secular policy or philosophy like, say, capitalism. It is, by definition, religuous. Our Constitution does create special protections for religious beliefs (and race, creed, color, national origin), unlike philosophical beliefs. Therefore, it must be treated differently, regardless of a majority opinion.