If Trump were an effective leader, with nothing to hide, and with the good of the country and the American people really in his sights, here's what a real president would do:
1) Release a list of all associate contacts with Russian officials or those within the Russian sphere of influence (i.e., Ukraine). Detail who met, where, and when they met, and what was discussed. If there is nothing to hide, that shouldn't be a tough thing to do. Remove the specter of doubt and nefarious activity.
2) Since he has (kind of) acknowledged Russia's role in the hacking/leaking of emails during Hillary Clinton's campaign, say to the American people that" because of the intelligence pointing to Russia's involvement, that for the good of our democracy, a full-scale investigation will be launched to determine the extent of the interference and the players involved." Again, if there's nothing to hide, this should be a no-brainer for the good of our country and for the credibility of future elections.
3) His statements that he has no business dealings with Russia could be at least somewhat addressed with the follow-through of an earlier (and now reneged) promise, to release his tax returns. Yet once more, someone with nothing to hide in those regards should do what earlier he said he would do.
But he won't do any of these things. And with these actions (or inactions), he has astoundingly proven that he does not work toward the good of the country or its people.
See? He's not a real president.
