Charles Kenny situates most Americans in it:
[B]y global standards, America's middle class is also really, really rich. To make it into the richest 1 percent globally, all you need is an income of around $34,000, according to World Bank economist Branko Milanovic. The average family in the United States has more than three times the income of those living in poverty in America, and nearly 50 times that of the world's poorest. Many of America's 99 percenters, and the West's, are really 1 percenters on a global level.
Matt Collin believes this sort of argument won't persuade people to support more foreign aid:
Kenny gives the welfare of people within and outside of the US equal weight. … I think that most people just don’t feel the same way: average levels of altruism for foreigners are certain to be lower than for other citizens, so we should be wary of making arguments which are too dependent on non-discrimination. People still see citizenship as part of a social contract – we’re all in this boat together, even if we were randomly assigned to it. Those that ended up in leaky boats are not our immediate concern ([though that's] not the way I feel).
(Map of countries resized to level of wealth in 2002 by WorldMapper)