Doesn’t matter, if he released his returns the Dems WILL find something, perhaps he didn’t “give” enough to charity (the horror) to Trump using “loopholes” to reduce his tax burden. SOMETHING will be found.
The Left will say nasty things about Trump whether he releases the tax returns or not. But with them in the public domain at least he can point to a piece of hard evidence (the tax returns) to refute the Left’s claims. Having some evidence in your favor is better than having none.