I'm not sure what your question is. No downside to what? The tax bill or The Fair Tax.

The only downside that I see to passing the current tax bill is that revenues to the government will increase and Congress will overspend just like they always have.

The jury is still out on whether the tax bill will add to the debt so there's no point in even discussing that. Studies and polls have been wrong about so much recently that they really should be ignored. Most start out with an agenda and questions are asked and information input to support a specific conclusion.

Government spending is what causes deficits. There is simply way too much pork spending. We also have the federal government involved in too many areas that our founders never intended it be in control of.

We don't have an income problem, we have a spending problem. And most of the spending is done with an eye toward being re-elected and/or keeping a particular party in power. Don't be fooled by believing that people in Congress have the best interest of the American people in mind. They are interested in taking as much money as possible from us so that they can take credit for giving it back. It's all a big game.