Not that any of those guys got a shot but Weld and Sanford both scare him, I think "Gentleman" Joe Walsh is trying to make a comeback using a different approach, go after Trump which will not go over too well with the teabaggers he relied on to be a one term congressman. Walsh wants camera time for himself...
"Teabaggers" didn't have much to do with Walsh's election. Obamacare did.
After that. The congressional districts were gerrymandered by a Democrat state government. Which is what usually happens.