Greenspan, testifying on immigration reform before the Subcommittee on Immigration, Border Security and Citizenship, said more skilled immigration was needed "as the economy copes with the forthcoming retirement wave of skilled Baby Boomers."

This hearing was called by subcommittee chairman, U.S. Sen. Chuck Schumer (D-NY), to encourage the U.S. senate to take up immigration, despite the economy. Greenspan was the marquee witness.

Greenspan provided a list of reasons for increasing skilled competition. One in particular, would help fix a problem -- the housing bubble -- that grew on his watch as Fed chair, a position he held from 1987 to 2006.

Skilled workers from overseas "will, out of necessity, move into vacant housing units; the current glut of which is depressing prices of American homes," said Greenspan. In 2005 Greenspan characterized rising housing prices as "froth."

But what will likely be the most controversial aspect of Greenspan argument will be his call for . He said that increasing the numbers of skilled workers from "would address the increasing concentration of income in this country," he said.