Here's the defining factor: will Google stay an American company if their business model is threatened? If Google no longer has the ability to operate at their fullest potential, they may remove themselves as a United States corporation. Google can't simply remove all piracy links (it's physically impossible due to the number of attached pages) and they may be forced to operate outside of the US.
Now, if we continue on with the current legislation stating that only non American sites will be blocked if found hosting illegal content, what is to stop a piracy site from moving to the United States to set up shop? Clearly these sites exist in the US and there is little to nothing done to American citizens that download pirated content, only to hosts. To destroy piracy is to imprison every citizen in the United States to ensure that there are no capable pirate hosts.
Now back to Google: there is no way that SOPA can create legislation that goes against Google. Google is in the top 5 if not the top 2 most viewed pages everyday and controls literally every social media plugin (YouTube, FaceBook, Blogger, Maps, etc). If the United States sole goal is to remove pirated content, they may lose Google to a foreign nation, and thus lose all sales for music producers after their content is no longer displayed to the masses.