I think most agree that wages for traditional blue collar jobs are on the decline . . .?

Weight the following factors from most likely cause to least likely cause: Increased manufacturing base in China, Lack of educational opportunity, Illegal immigration, and Natural economic evolution.

For instance, do you think the manufacturing operations in China have directly decreased the need of "cheap" labor within the U.S.?

1) Increased base in China 2) Natural Economic evolution 3) illegal immigration 4) lack of education

It really depends on what part of America you're referring to. For example, down here near Mexico, illegal immigration's the main cause. China is a competitor still regardless of their product safety issues. Lack of educational opportunity, not so much: even the poorest in the USA can get a basic education through high school.

Economics have a way of correcting themselves over time. What you are seeing is the market reacting to increased competition from overseas and a glut of cheap labour available. When those factors combine, wages will decrease.

Blue collar jobs are on the wane because of outsourcing and taxes.
Corporations will go wherever labor is cheapest and taxes are lowest leaving us basically screwed.

So are white collar jobs. Globalization is labor arbitrage and the American middle class is being destroyed - on purpose. There is no natural economic evolution involved in this - the billionaires just get greedier and greedier.

Wages for everyone seem to be on the decline.
My husband used to work in a very highly skilled machine shop that did mostly short run ( One or two pieces) manufacturing for the US military.
He was making more money 20 years ago and working half as many hours has he does now.
In other words we both work now to make as much as he used to make working alone.
What has happened I would love to know.