Not a lawyer, but I found the majority opinion's position on "regulate" much more compelling than the dissent. In particular, the majority's argument that "regulate" is a pretty common function of the executive branch that in no other context implies the authority to tax (tariff), which is a pretty clear Article I power. The majority also convincingly argued that it seems unreasonable to interpret a law to broadly delegate Congressional power to the Executive branch without Congress making that intent explicit in the law. The dissent not only didn't make good counter arguments even read by themselves, but the majority opinion did a pretty good job refuting those arguments specifically.