This is indeed a very interesting and significant finding.  But please don't muddle it by repeating this piece of misinformation:

The broad support for Murtha's plan also stands in sharp contrast to the November vote on his plan in the House of Representatives, when only 3 members of Congress actually cast a vote in favor.

As Media Matters For America noted at the time critiizing how the GOP spin was repeated in the media:

Hannity falsely referred to Republican resolution as the "Murtha amendment"

On both his television and radio show, Fox News host Sean Hannity referred to a congressional resolution calling for the immediate termination of U.S. troop deployment in Iraq as the "Murtha amendment." But the resolution in question was not sponsored by Rep. John P. Murtha (D-PA). While Murtha had introduced a detailed measure that called for the withdrawal of American forces from Iraq "at the earliest practicable date," his resolution bore little resemblance to the Republican-sponsored measure Hannity was discussing. This one-sentence resolution -- described in news reports as a "political trap" and "aimed at embarrassing war critics" -- simply ordered "that the deployment of United States forces in Iraq be terminated immediately."

Read MMFA's full and quite detailed account here.