Obama stated he was against SOPA anyway,
"WASHINGTON-President Barack Obama has said that we would not support the controversial SOPA (Stop Online Piracy Act) that would allow the justice department to force search engines from linking to sites that were accused of copyright infringement and require Internet providers to block those sites as well."
While he can not stop the bill he has expressed how he's against it. Hence why it's been pulled IMHO.
/Czeldabolg