See what your quotation is doing there? It's conflating the period from 1994 onward (the period after NAFTA and the WTO became law, and international trade picked up sharply in the US), with the 1980s and early 1990's -- an era before that trade liberalization, when the big policy changes were things like upper-class tax cuts, the erosion of the minimum wage, and aggressive action by the president to gut labor unions and cut social spending. In the 1980's through early 1990's, income inequality rose rapidly, incomes were stagnant, poverty increased, and unemployment rates were persistently high. After NAFTA and the WTO, income inequality grew at a MUCH lower rate, poverty fell, incomes grew robustly, and unemployment rates plunged. If you need a link to the Census's GINI index data to confirm for yourself, let me know, and I'll provide it.