Not a chance

There is a snowballs chance in hell that Donald Trump will appear before the House committee investigating the January 6th insurrection; to imagine otherwise is to entirely misunderstand Trump. Yes, he has said he wants to appear to make is case but that's his usual gas-lighting bluster. Such proclamations come without risk to him just as do his trademark lies made in the media. But what had become clear is that when he faces real legal jeopardy, he pleads the 5th. 

Testifying under oath before the January 6th committee would mean facing questions about his role in the insurrection. Given the evidence the committee has unearthed so far, answering truthfully about his involvement and his actions would amount to a confession as to his role in the plot to subvert the results of the 2020 election. Answering untruthfully would likely be less damaging but would none the less represent a legal problem for him.  

His most likely play is to first ignore the subpoena and then to challenge it in court to create delay sufficient to run out the clock past the mid-terms. If that fails he will dare the January 6th committee to try to enforce it, something they may hesitate to do given his ardent supporters passion and their potential for violence.    

The only circumstance in which he would testify would be if he were to adopt the position that the January 6th committee, and by extension the legislative branch of the government, had no legal authority to question him as an ex-president. While that is clearly bonkers, it is the argument routinely used by autocrats when they face judicial proceedings; they consider themselves above the law. While it is possible that Trump is that delusional, his past practice suggests that he hasn't taken leave of his sense to quite that degree. 

Of course, I could be wrong; either way it will be another Trumpian spectacle that will challenge the robustness of our institutions.