There are really three different types of discussions that lead to legislative results, values discussions and what I would call objective discussions. Values discussions are things like should the federal government recognize gay marriage. This is really a question of “fairness” (subjective), “equality” (subjective) and “morality” (subjective). On the flip side are things like global warming. Global warming is a fact based thing. It either is happening or is isn’t, and the only people that are qualified to make that determination are scientists and researchers.
Most issues that Congress deals with are a mixture of the two. Take taxes as an example. The goal is to fund some level of government (though of course how much and on what is debatable). The values come in when one is deciding one items should get taxed. For example, should bullets be taxed, or cars, or food. The objective bit is to examine the effect of the taxes. Is it not a matter of opinion if a tax on cars will vary the amount of cars sold by a given percentage. Its a question for economists. Now, there will probably be disagreements between economists, but that is reasonable. What is not reasonable is express an economic viewpoint that has no basis in economic literature. For republicans to say that “tax cuts pay for themselves” is interesting, but the science is not behind it. It should be an unacceptable viewpoint. When the CBO came out a report saying so, republicans tried to quash it. Though the retraction was later retracted, the point is that politicians (I don’t think that its just republicans) are predisposed to try and discredit research that disagree with their positions.
It would be nice if bills were actually debated in a rational sense. Instead, what we get is variations on “If you give me some piece of pork for my district, I’ll think about signing” and “It might make the other party look semi-decent, and so I won’t sign.” If you look back in history for great legislators, we find people like Henry Clay (aka “the Great Compromiser”) who were known for (surprise surprise) compromise and getting things done that crossed party lines.
There a lot of problems with this country, and those problems need dealing with. We don’t need more manufactured crises that get solved at the last minute only create more later. If legislators were forced to defend their views on a strictly logical basis, the quality of the discourse would dramatically improve. That does not mean that they are not allowed to make value calls (like the value of a human life is infinite for example) but it does mean that if you do, you have to be consistent (no-one should ever be allowed to create a product that can possibly every kill someone in any way, i.e. no knives, etc).