87 percent of Americans describe themselves as either "middle class," "upper-middle class," or "lower-middle class." So it's no wonder politicians use it. About nine out of 10 Americans think the politician is talking about them. But nearly half the population wouldn't be able to cover an unexpected $400 expense through savings or their credit card and would have to cover it by selling something or borrowing money.
A quarter of households are 'asset poor', meaning that they wouldn't be able to subsist at the poverty level for three months following a job loss, medical emergency or sudden need to fix car. This measure includes assets like home or business.
If you only count liquid assets, then that number jumps to almost 44% of households that wouldn't be able to make it in three months.