Endorsing a piece of legislature is very different than actually voting on it. There's a lot of political back and forth for every bill that passes and endorsem

Endorsing a piece of legislature is very different than actually voting on it. There's a lot of political back and forth for every bill that passes and endorsement is just an early phase when the whips start gathering numbers for who supports a given bill vocally and officially. This will put pressure on the comittee to put the bill on the floor as soon as possible and with little modification. Once it's slated for the floor vote, the whips and bill sponsors (even more involved than endorsement) will round up the rest of the votes including those who would have voted yes anyway, but couldn't endorse or sponsor for political reasons, and those who need to be convinced through favors and whatnot. Remember, senators are elected by all districts in a state so they have to be more careful politically.