You're going to hear a lot today about the contrast between George Romney's 12 years of tax disclosures and his son's 2 years. Keep this in mind:
George Romney expected (or hoped) to run for president against Lyndon Johnson, the exemplar of the financially dirty politician. Over a lifetime in politics, never working in the private sector, Johnson had accumulated a fortune of (by some estimates) the equivalent of nearly $100 million in today's money. Romney wanted to make a point: Unlike Johnson, he was no richer at the end of his public service than he had been at the beginning. The point was brightened by the murk and gloom that then surrounded campaign finance: Who gave how much to political campaigns was then a closely guarded secret, virtually no disclosure at all.
Keep this in mind too:
While Newt Gingrich may disclose his tax returns, most of the things you'd want to know about Gingrich's affairs are not contained in those returns, but instead in the financial history of the interlocking Gingrich enterprises—some of them theoretically non-profits—that have collected tens of millions of dollars over the past decade. The enduring relevance of the House ethics report about Gingrich is the light it sheds on his method of raising money in one place (often a place that can issue tax deductions) to spend in another palce, sometimes on purposes that are in no way tax-deductible.