That's been the essence of the message of some here at FR, too, sadly.
Initially I thought he would veto it, and was disappointed. However, someone pointed out that we need to have this go to the Supreme Court while we still have a fairly conservative majority. If a conservative justice dies or retires, we could be in a position to see this ruled on AGAINST us. I think the decision was made to get this out of the Senate and to the court ASAP, and also remove the issue from the fall campaign.