The last time tax receipts as a percentage of GDP were below 17% was in 1959 when they dropped to 16.2%. The last time they were below 16% was in 1950 and 1949 when they were 14.4% and 14.5%. To claim "Since WWII, tax revenues have stayed within 15 to 20 percent of GDP" is completely false and utterly dishonest. It is more honest and accurate to say receipts average between 17%-19%, and in the 90's were in the high 19s and hit 20 by the end.
However you phrase it, we have not seen tax receipts this low as a percentage of GDP since the end of WWII. That is a fact.
Additionally, you are utterly wrong about Laffer and Reagan. From 1980-82, by no means economic boom years, receipts never dipped below 19% of GDP. From 1983-1986, they never went above 18%! Just like with the Bush tax cuts, tax receipts went down not up.
Lastly, I am amazed by your spin on the fact that half of Americans don't pay federal income tax. If that isn't proof that taxes are their lowest in generations, I don't know what else to tell you. You're simply ignoring reality and history.
I am not in any way amazed by your spin on facts...I've come to expect it.
Nevertheless, let's take 'em one at a time:
1) Glad we agree that all Americans should pay an income tax. Chalk one up for bipartisan support.
2) Regan's tax rates included both increases and decreases and were not fully implemented until 1983. And what do you know, receipts stayed about the same. Amazing, isn't it?! The people has less taken out of their pockets but the government still got its revenue. And yes, we stayed within that traditional 15-20 percent range.
3) So you're saying I lied because since WWII, we saw 14.4% in 1950, which isn't technically 15%. You got me. Mia culpa.
But hey, at the end of the day, I'm sure your degree in economics and experience in the field outpaces that of Art Laffer...I'm sure.
1) We do agree on this point. However, I'm sure we disagree on how to go about it. For the record, I am in favour of raising wages before we raise taxes on the working class.
2) Again, no. You are ignoring history. After 1983 tax receipts dropped to below 19% and did not rise above that level until 1997! In fact, in 1981, receipts were 19.6% and in 1984 they were 17.3%. That's a substantial drop that you are choosing to ignore. Why is that? Oh right, because ...
3) You are arbitrarily picking a range. You've decided to use 15%-20%, even though since WWII, there are only a couple instances of levels as low as 15% or as high as 20%. If you were being honest, which you aren't, you would use the average and 1 standard deviation, which would get you a range of 16.4%-19% (17.7% being the average). Using that range, you would see we are currently way outside the norm.
As for your hero Art Laffer, you know he drew his famous curve on a napkin as a joke, right? It was never meant to be taken seriously. But, since you are taking it seriously, the least you could do is be honest with yourself. The Laffer Curve is a CURVE. Which means on the left side as tax rates drop so do tax revenue levels. That's what Laffer was saying and that's what you are choosing to ignore.
Whether you like it or not, we are on the left side of the Laffer Curve.
edit: links to sources
Historical Federal Receipt and Outlay Summary
Political Calculations: Is Hauser's Law Still Valid?