I have long defended the Senate's rules allowing filibusters, though I have criticized its excessive use in recent years and for pretty trivial issues. The filibuster against legislation disapproving the Iran nuclear deal, however, was a proper use on a major policy issue -- and I am pleased that the filibusterers succeeded in blocking the measure, which would have undermined American and Israeli security and greatly increased the danger of another major war in the Middle East.
Senators deserve the right, when in minority positions but feeling deeply about a major policy issue, to obstruct through the filibuster, provided they can get 40 or more colleagues to agree.
I still favor eliminating the filibuster on the motion to proceed -- that is, to take up a measure. And I wish the rules would be changed to force the objecting 40+ to show up in the dark of night to keep the debate going, but the underlying rules are good for our democracy.