Liquid Democracy: “how it would be implemented?”: well, as usual, the concern is that there should be no room for cheating, that your vote gets counted the way you expected it to be. So you need a vote-totaling system that is accurate and fraud-proof. General proposals say “do it on the blockchain”, which seems plausible to me. So yeah, “software”.

The harder part is installing it into the political system. But that actually seems doable in the US: elect representatives/senators to state/federal houses/senates who promise to act as puppets, beholding to the liquid vote-totals. This appears to be 100% legal in the U.S. and requires no change of any existing laws. So step one is “make people aware”, and step two is “start installing such puppets into houses/senates”.