Um, this is rewriting history. The "boom" of the 80s was from August 1982 to October 1987, using the stock market as an indicator. The markets then went into bear mode really until late 1995. I was trading on the exchange in those days and remember it quite well.
Supply-side fantasies had nothing to do with genuine expansion. They did have something to do with excess speculation, which is what produced the 1982-87 "boom". The Clinton "boom" of 1995-2000 was based not on "contractionary policy", whatever you mean by that, but on the fact that productivity finally soared due to advances in technology and the relentless downsizing of corporate workforces during the 1988-1994 contraction.
Really, it does no service to anyone to make these sweeping and incorrect assessments of economic history.
In regards to the 1980's, I was actually not even thinking of the stock market so much as the country's GDP - which I stated in a previous post I believe. How many presidents can you think of who inherited as much of a mess as the stagflation of the 1970's and turned it around in less than two years?
I think that every major economist (no matter what school of thought they subscribed to) would agree that cutting taxes by almost five percent of the nation's GDP would be a short term boost to the economy.
Note also that in my post I refer to 12 years of "uninterrupted expansionary economic policy", not an "uninterrupted expansion." I do agree that there were corrections to the economy in 1987 and again in 1991
By "contractionary," I mean anti-inflation. Contractionary policies usually involve increases in government spending (especially the kind of investment you refer to in your post), higher taxes, and tighter monetary policy. Although Clinton did leave interest rates low, I believe. http://en.wikipedia.org/wiki/Keynesian_economics
You are basically agreeing with my general point which was that specific government policies are only some of many factors that effect macroeconomic performance. If you'd like to speak of the Clinton Boom, there are other factors that contributed to it as well - not least of which was the opening of foreign markets.
I just think it's unfair to not give Reagan any credit for what was the most astonishing economic turn around since the 1950's.