While Block says that he has now stopped drinking and turned his life around, he has not entirely avoided scrutiny since then.
In 2007, Block was investigated for potentially misleading robo-calls against a referendum to raise money for school construction, although a prosecutor eventually decided that the case was not strong enough to pursue a trial. In 2010, a liberal group in Wisconsin accused Block of trying to suppress minority and college voters, although officials declined to investigate.
Block denied wrongdoing on both counts to the AP.
Cain has stood by his chief of staff, speaking glowingly of Block both in his recently published book and on the heels of the now-notorious campaign video.
"We have a saying in my campaign — let Herman be Herman. This is the attitude that I have when I do debates. This is the attitude I have when I do interviews: Let Herman be Herman. Mark Block is my chief of staff. And we also say, 'Let Mark be Mark,' " he said on Fox News.
"Mark happens to be a smoker. He knows it's a bad habit but he smokes. And so, we weren't trying to send any subliminal message whatsoever. Many of us found it hilarious because we know Mark Block."
In Cain's book, This Is Herman Cain!: My Journey to the White House, he credits Block's outside-the-box thinking for campaign successes. The strategy has worked so far — according to a Fox News poll released earlier this week, Cain leads the Republican field with 24 percent of those surveyed.