Today's speculation:
Because there are some years when his donations to the LDS church are more than 100% of his taxable income.
Which is not possible for most of us ... but with offshore accounts in the Caymans and stock market losses, all things are possible.
And what this will point out is that Willard M. Romney used one number to compute his income for tax purposes, and a different, much larger number when computing his income for tithing purposes.
I'll bet there are several such years to be found, where the amount given to the church is entirely out of line with claimed taxable income.
And if Willard uses a small number to determine his tax liability, and a large number to determine his tithe liability, does that not suggest that he is a Mormon first and an American second?
Those are two subjects Romney desperately needs to avoid; discussion of his religion, and discussion of his low tax rate. Combining the two makes for a toxic topic.
So much for today's speculation. Tomorrow I can try something else. Guessing why Romney won't release the sort of information he would demand from any company Bain considered investing in will continue until the returns are public.