This is meant to play to his base, and if loyalists run the “investigation” they will make up fake conclusions and even fake evidence if they have to.
What groups should be doing is starting mass drives to get everyone registered with the “mandated” ID, starting right now and not in an election year. There have been many stories about the Herculean efforts some people go to and are still denied ID, but those plus the long lineups at understaffed and insufficient locations would make for good stories constantly over the next 4 years plus millions would be registered to vote by 2020. Imagine lineups of hundreds of people everyday for four years on the news constantly who are opposed to Trump, and constant stories of them being denied ID will make in impact bigger then Trump’s lies. A picture is worth a thousand words, constant video evidence is worth a lot more.