A constitutional obstacle to court packing would be tremendously valuable, but it might have downsides as well.
Over at the New York Times Room for Debate feature, the topic is: If the U.S. Constitution were being written today, what would you omit, add or clarify? My own contribution is to end Congress’s monopoly on proposing constitutional amendments by fixing the convention method of amending the Constitution. It currently does not work, because state legislatures fear a runaway convention. I wrote about this issue at the Liberty Law Forum, which also included a couple of responses.
The Room for Debate topic included a variety of interesting answers. One was by Randy Barnett, who proposed to amend Congress’s Commerce Clause authority so that it “shall not be construed to include the power to regulate or prohibit any activity that is confined within a single state regardless of its effects outside the state.” This is definitely a good start, but I would want to add some checks on Congress using other powers (such as the Taxing Power and the Power to Enforce the Law of Nations).
Jamal Greene also proposed 18 year term limits for Supreme Court Justices, which I also support.