Sure enough, after being thoroughly beaten up on it, Simon is being forced by enormous political pressure to (partially) give in. But Simon still doesn't get it: by continuing to limit the access to his tax records, he allows Davis to keep the issue alive. In some ways this half-measure is even worse; it really makes it look like Simon is desperately trying to hide embarrassing facts.
Whatever political damage might be contained in Simon's tax returns can't begin to compare to the political damage he's suffered by trying to withold them. A competent, experienced politician would have released the records months ago without being asked. An incompetent, amateur politican would wait until his campaign was severely wounded and then release the records, thereby assuring himself the worst of all possible worlds.
Are Simon and Davis both competing to lose the election?