An economist working for a recent president, once argued that , trade deficits are always bad for the economy. He said something like " look at the national income identity, y=c+I+G+(x-m). The last term is the balance of trade. If imports, m, are bigger than exports, x, we have a trade deficit and that last term is negative, meaning that it's lowering gdp." His math is right but his economics are wrong. Explain.(it doesn't matter which economist and which president. This question is about the ideas, not the politics)