Should lying in politics be illegal?

Politicians have probably lied to us from the very beginning, but lately it seems to be an epidemic. You know it’s bad when Fox News calls out Ryan for lying. From the article:

”...to anyone paying the slightest bit of attention to facts, Ryan’s speech was an apparent attempt to set the world record for the greatest number of blatant lies and misrepresentations slipped into a single political speech.”

I’m sure there are some Democrats lying, too.

I understand that prohibiting lying in a speech would probably run afoul of the first amendment, but how about in political ads? No other advertisers are permitted to outright lie, so why are politicians exempt from that standard? Should/could the ads be vetted by independent fact checkers before being aired or printed?