As a precondition for any presidential debate, Donald Trump must immediately make his IRS filings available to the press and to the public.
Just as there is no constitutional requirement for candidates to make their tax returns public, there is no constitutional requirement for candidates to debate one another. Both are only a matter established custom, one of which Trump has seen fit to violate.
Joe Biden should not even begin to consider a debate unless and until Trump releases his tax returns in full. Then, and only then, he may wish to discuss the possibility.
Peter Scotto
South Hadley