I think you are confused. Congress created the monstrosity that is the US Federal tax code, and only Congress can fix it. As folks where I’m sojourning this spring on the other side of The Pond would say, “not bloody likely.”
Short of a Convention of the States promulgating a amendment to repeal the 16th Amendment and its subsequent ratification, I don’t think there is a politically feasible way of simplifying the tax code — every deduction and credit has a vocal constituency that can sway a goodly portion of Congress.
Ok, I can understand you disillusionment, but why don’t you give Donald J. Trump a couple of years while you organize the Convention of the States. The CoS is still a good idea to get rid of the 16th and 17th Amendments, but a lot of good can be done just cleaning out the Code of Federal Regulations.
I disagree, I think the right President could sell Congress on a Flat Tax program. Why? Because since 1913 Congress has made a career out of tax policies changes. So with the slate wiped clean, groups would want changes made to correct the Flat Tax program and now Congress would have decades to milk the system of change demands. So the Americians would get maybe 10 years of basic flat tax before changes which maybe long enough to show a simple tax system works for everyone.