"If there was a Democrat in the White House, and this was going on, we'd still be doing this," Mellencamp told The Herald-Times of Bloomington in an interview published Sunday.
"This is a protest. It's a protest about the abuse of what we feel are American values (search). And in this case it just so happens that, yes, this is a Republican president, and yes, the proceeds will go to efforts to defeat that Republican president."
A July fund-raiser that raised $7.5 million for John Kerry (news - web sites)'s presidential campaign included Mellencamp performing "Texas Bandito," which refers to Bush as "a cheap thug."
"I wasn't very politically active before this administration," Mellencamp said. "I had political views, but I always used to say, 'I don't want to hang on anybody's cross or stand on anybody's soapbox. Whatever I need to say, I'll say in my songs.' But things are different now."
Mellencamp said a growing intolerance for opposing viewpoints in this nation inspired his participation in the "Vote for Change" (search) series of 34 shows in 28 cities.
Mellencamp, a southern Indiana native, has written songs on social issues, such as "Pink Houses" and "Rain on the Scarecrow." He co-founded Farm Aid (search) in 1985 with Willie Nelson and Neil Young.