We should ask them at every opportunity whether it was a mistake or a deliberate act of defiance of the people who elected them.
Their outright defiance is a measure of how confident they are that there will be no effective retribution. If you've ever had experience negotiating, you know the best negotiator is someone who has nothing to lose.
We should be alarmed not only by the sheer defiance of the Senate bill, but by the underlying reasons for their confidence. That's the most frightening aspect.