Who coined the recent phrase "It's the economy, stupid!"

Factual Questions
1

Used in reference to the POTUS, usually. Is this from the Clinton years, or more recent?

2

http://www.heritage.org/Press/Commentary/ED051696b.cfm

"Presidential advisor James Carville, the highly regarded Democratic political operative from Louisiana’s bayou country, helped keep the 1992 Clinton campaign in focus and “on message” with a simple four-word phrase, “It’s the economy, stupid.” "