PCNA, the House's (worse) version of CISA, passed with similar margins in April.
Obama has publicly supported the bill all year.
As much as HN and Twitter wants to believe CISA was enacted in some shady backroom deal, the process that actually occurred, including publicly available amendments and months-long review, is pretty close to "Schoolhouse Rocks".
The debate on CISA was over. Thankfully. The only debate left was how close CISA would come to PCNA, with its broader law enforcement ties and vaguer language (EFF claims PCNA would have in some cases authorized large private companies to "hack back" computers they believed had been trying to hack them). Instead, Senate's CISA is the law of land almost verbatim to what they passed --- in a drawn out, public process --- in October.
Later:
Someone downthread asked for a summary of the bill. I did my best to strip the legalese out of it: