One of the more baffling lines Republican lines of attack against Supreme Court Justice Elena Kagan during her Senate confirmation hearings was the accusations of guilt-by-association with civil rights hero Justice Thurgood Marshall.

Many of Marshall’s critics tried to backtrack after realizing that criticizing the man who led the effort to desegregate American schools, and eventually became the first African American Supreme Court Justice, wasn’t exactly wise. But we don’t think they should be allowed to bury their attacks.

This week, People For went on the air in Iowa with a radio ad about Sen. Charles Grassley’s participation in the GOP’s anti-Marshall crusade. You can listen to it here.

And for more on why Grassley’s attacks on Marshall were so off-base, read People For board member Julian Bond’s op-ed in the Des Moines Register: “GOP attacks on Marshall echo anti-civil rights message of 1960s.”