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I think one of the problems (and lessons forgotten from the 1930 depression) is that the Feds should have spent a lot of the stimulus money. It all went to the states - who haven't spent 1/3 of it yet. That means 2/3s of the money is just sitting there (well in California it is probably long gone).
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In the 1930s FDR created the TVA (Tennessee Valley Authority) to build dams, water projects and bring electricity to a a 10 state area. He created the Civilian Conservation Corps (CCC) to put rural men at work building roads, trails and rehabbing National Parks. He had works projects by the score.
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I know hindsight is 20/20, but if some of your goals are high speed rail (which actually makes sense) and national infrastructure - then do it. Don't ask the states pretty please to do it. The states (and Congress) are full of overfed, pompous local politicians and suck-ups who are hoarding the money until election time.
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My 2 cents.