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Advertisers are fleeing his show, radio stations are refusing to broadcast his program, and the president is condemning his comments in large part because Rush Limbaugh used the words "slut" and "prostitute" to describe a 30-year-old Georgetown law student.

But apparently this nationwide outcry over these "insulting" words, as Limbaugh himself called them, was not enough to prevent another syndicated talk radio host, Robert F. Kennedy Jr., from slinging the very same insult.

"Speaking of prostitutes, big oil's top call girl Sen Inhofe wants to kill fuel economy backed by automakers, small biz, enviros, & consumers," Kennedy, a senior attorney at the Natural Resources Defense Council, tweeted Tuesday night.

The tweet was apparently in response to a letter Sen. James Inhofe, R-Okla., sent to Environmental Protection Agency administrator Lisa Jackson, accusing the administration of "recklessly" implementing emissions standards for cars.

Kennedy, an ardent environmentalist, was on President Obama's short list to head the EPA in 2008. He has also flirted with a possible run for Congress.