They aren't doing this work at the moment, which is why he uses could- they're unemployed and not doing the work."Right now, there are millions of laid-off construction workers who could be repairing our bridges and roads and modernizing our schools"
The Act had not been passed at the time he was speaking, so will is too certain because of the risk of the Act not getting passed.The American Jobs Act would cut taxes for virtually every worker and small business in America
He's not using them to sound more formal, but to talk about things that are not real- the work is not being done and the Act had not been passed.
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