I take issue with statement sir, political comics, just like webcomics, are subject to the %90 rule, which states that %90 of anything is pure shit. I'm sure its always been that way, even back in the idealistic times you speak of.
A good example would be my local paper, the San Antonio Express, which features two cartoonists, Branch (who utterly sucks on a level comparable to Rall) and Leo Garza, who publishes a wonderful little four panel called Nacho Guarache (although you'd have to live in South Texas to get 95% of the stuff he talks about, and it is hit and miss sometimes. Sadly, like all comics, NG seems to be entering is final "turning from great to utter crap" stage, but his early work is awesome.) Branch on the other hand, gets syndicated nationwide. He also does this neat little Sunday strip called Aztlan featuring an Aztec warrior (complete with leapord skin outfid and obsidian battle axe) displaced from his homeland and navigating the absudities of modern day San Antonio politics.
You can't say no to super-deformed Mexicans.
Like I said, they're out there, you just have to keep in mind that like webcomic artists, most political cartoonists have no idea what they're doing (yet unlike most webcartoonists, they're getting paid for it)