Is a Progressive Tax Code Constitutional?

I'm preparing to write substantive, spiritual, biblical posts, continuing the series that I've already started (I don't know how many exactly I've got going, but I know of a few at least).  I like to do that, but right now I've got extra stuff, more than normal, in the way of a new, old house that I'm remodeling while I do everything else.  On Saturday, I built a small frame to pour quick setting concrete to seal a crack on the outside of the foundation of the garage, where water has been seeping in.  Next to it I built a small French drain to help the water divert around the area.  Then I sawed a hole through the stucco of our house next to where our dryer would be to put in a dryer vent (there wasn't one in the house).  I went to the church to work on the church calendar and other things, and found out there was a small leak in the plumbing, which required me to tear out some drywall to get to that.  So lots is happening. This is an easier one to write, because I don't have to look at much to write it, but it's something that has been in my head, so I'm going to go ahead and release the thoughts and see what you think.

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The French Supreme Court recently overturned the French tax code, saying that the 75% taxation on the income of the wealthiest was unconstitutional.  That got me thinking as to the constitutionality of the progressive tax code in the United States.  I don't know if it has been challenged in the Supreme Court here, but maybe it should.  Here's where my mind went with this.  Bear in mind that I would be hurt financially by a change in the tax code.  Right now it benefits me a lot.  However, I think it's wrong, so I oppose it.

To start, I don't think that tax code is a constitutional issue.  However, based on how the Supreme Court has interpreted the constitution, it might be, and it probably is.  And when I write that, I'm considering the fourteenth amendment, that since its writing, has been used to argue a number of positions that have had nothing to do with the fourteenth amendment as originally written.  Some have called this the hijacking of the fourteenth amendment.  (Wikipedia has the text of the fourteenth amendment for easier reference.)  If you remember, the fourteenth amendment was used in the Bush vs. Gore case that decided the 2000 election. The argument said that everyone should have the same exact voting standards in Florida, that the counting of the votes should be the same for every single person.  Thoughts of the fourteenth amendment amalgamated for me in the argument against a progressive tax code and how the French Supreme Court ruled.

There is precedent in the Supreme Court, I believe, in the equal protection clause to say that everyone deserves equal taxation.  The sixteenth amendment, which allows for federal income tax, is silent on a progressive tax, making the sixteenth amendment moot on this point.  However, why couldn't the fourteenth amendment be used to argue that a progressive tax does not protect the rights of those with higher incomes?  Higher income people will not be protected by Congress, because they are such a small minority.  Are they protected by the constitution as presently interpreted?