It's unsurprising but still peculiar that both wings are prone to featuring the most simplified of arguments about taxes, which fail to incorporate the notion of optimizing tax rates. Or at least trying to do so.
I don't want to focus on the merits of either side's simplified arguments, Instead I'd like to try to give folks a place to start, a reference point from which they can evaluate the insight and good faith of other folks arguments, Expect many of the arguments you see to be uninformed at best, and biased at worst.
Fortunately, Ezra Klein can helps us out by askingWhere Does the Laffer Curve Bend?:
With the Bush tax cuts due to expire soon and debates about raising top rates further to cut the budget deficit soon to follow, the Laffer curve is bound to come up again. The idea, popularized by economist Arthur Laffer and writer Jude Wanninski in the 1970s and '80s, is simple. Tax rates of zero percent produce no revenue, for obvious reasons. Rates of 100 percent should produce no revenue either, as no one would bother making the money that falls into that bracket knowing it would all be taken away. Thus, presumably, there is some rate in between the two that maximizes revenue. Go above it and revenue would fall because people would avoid taxes or stop working; go below it and revenue would fall because less money would be taxed.
This is the place to start, with an understanding that raising or lowering taxes could potentially increase or decrease government revenue.
From there, it's also worth noticing that increasing or decreasing government revenue is far from the only important matter when it comes to tax policy. If you click through to Ezra's article in the link above, you'll find many thoughtful and useful and brief! summary thoughts that are worth considering when you think about taxes, what is fair, and what is necessary for our nation. So check them all out.
In closing, I'd like to call attention to one notion that I think is especially important to consider alongside government revenue. Fortunately, one of Ezra's quotees has done some of the work for me:
My guess is that that the short-run answer and the long-run answer are quite different. For example, if you raised the top rate from 35 to, say, 60 percent, you might raise revenue in the short run. Over time, however, you would get lower economic growth, so the additional revenues would fall off and eventually decline below what they would have been at the lower rate.... I will pass on offering a specific number, as it would require more time and thought than I can offer just now, but I will opine that I think the long-run answer is actually more important for policy purposes than the short-run answer.
In other words, it is at best risky to focus only on maximizing government revenue. Over time, higher tax rates may adversely effect economic activity to the point where we are worse off down the road for having optimized revenue a few years earlier.
If you want a reasonable baseline for evaluating the merits of tax policy arguments from politicians and talking heads and random blowhards, I think this makes a good start.