Trump is so clueless he fails to grasp that he has no choice about talking to Mueller investigators. The president arguably cannot be indicted, but no American is above the law, and that means if he were to decline an interview and were served with a subpena (which is exactly what they would do, possibly even a grand jury subpena, for which there is precedent), he would have to testify of be in contempt. Somehow I don't think Donald Trump, who is, as was pointed out on a couple of news shows today, basically a coward, would precipitate a Constitutional Crisis in all caps by triggering a contempt citation.
But all this is secondary to my main talking point lately which is... sure criminal investigation of conspiracy and obstruction of justice by Trump or Trumpists is worthwhile and important, and Congressional investigation into interference in the election in 2016, with an eye to what to do to prevent the same happening again is vital (and isn't happening), but DEMOCRATS NEED TO COHERE ON A CLEAR MESSAGE for the upcoming elections. Scared of Trump isn't good enough. We must present to the American people an agenda and a plan that is so clearly superior to the mess the Republicans have created that we wipe the floor with them in both the House and Senate elections, and in State Houses and Governorships across the land as well. And make no mistake, this is FAR MORE IMPORTANT than either the Mueller or Congressional investigations for the very real yes or no issue of whether we will defy protofascism and save our Republic.... OR NOT.