A politician should take from the march that action on gun laws needs to happen now. How they propose to do that is up to the politicians - not the marchers - and the politicians can then be judged or not at the ballot box.

Why you propose to judge voters rather than the politicians is beyond me. What do you propose to do if voters are deemed to have failed or succeeded?

Whether the march changes anything or not is again not up to the marchers. They are there to start something, to signify their anger. If sufficient voters agree with them then ultimately the politicians will act. If the anti-gun lobby becomes a much bigger voter pool than the pro-gun lobby then change could happen dramatically quickly. That will never happen without people organising and taking a stand.

Laws have been shaped by lobbyists in the form of the NRA or MADD - there's no reason these marchers can't be just as successful in the long run, unless they decide not to bother trying.