Why does the economy perform better under a Democrat?

It does! This article gives the eight measures of good economic management and the stock market statistics.

Don't panic because this is about economics. It is a really easy read that tells us that:

The results demonstrate why supply-side policies are sometimes called "trickle-down" economics. Corporate profits have soared 57.5% during the Bush administration, while workers' wages and benefits have increased a minuscule 1.57%.

In less than a year and a half, the Bush administration's sweeping tax cuts, passed by Congress in 2001, wiped out the federal government's 10-year projected budget surplus of $1.6 trillion. In 2000, the budget surplus was $236 billion. Three years later, the surplus had turned into a deficit of $375 billion.

Because Bush believes the free market will solve America's economic problems, he wants to gradually privatize Social Security and Medicare. To finance current government spending — after having given the wealthiest 1% of Americans 43% of the tax cuts — Bush is borrowing more heavily from the Social Security trust fund than any previous president. At the same time, the Treasury owes billions to foreign investors who buy Treasury bonds, and thus subsidize the national debt, which has soared by 29%, to $7.3 trillion.

The only exception that I have to this is that we really don't have a free market. Corporations are very heavily subsidized here, and many of the government functions that have recently been privatized cost more (way more) and provide inferior services while paying their employees far less .

go figure