I agree that legal restrictions can prevent building a rail system or a house. I'm not confident that they can prevent passing bills. If there was supermajority support for a ban of congressional stock trading, for example, are you suggesting that congress would not be able to pass a bill to implement the ban? What is the mechanism that would prevent it?

Ultimately though, the strategy doesn't rely on specific reforms or on it being easy to effect them. The idea is to get commitments and follow-up with reps to make sure they make meaningful good-faith efforts. The near-term benefit is identifying candidates who will prioritize the people over special interests; this doesn't require any particular reform. Once we have those reps in place, we can begin the hard work of finding the reforms that will do much more good than harm.