Here’s what Mitt Romney may be hiding by refusing to release his pre-2010 tax returns and (so far) his 2011 tax return.

It’s probably no coincidence that when releasing his 2011 tax return, President Obama also re-released his tax returns from the previous 11 years starting in 2000. Mitt Romney’s father, Michigan Governor George Romney, also released 12 years of income tax returns when he ran for President back in 1968.

At that time George Romney explained that so many years of tax returns should be disclosed because, “one year could be a fluke, perhaps done for show.” A reviewer of those tax returns back in 1968 noted that George Romney, “seldom took advantage of tax loopholes to escape his tax obligations.”

Unlike his father, candidate Mitt Romney has reluctantly disclosed only his 2010 tax return which showed he paid an effective rate that year of only 13.8% on income of nearly $22 million, a much lower tax rate than is paid by many middle-income professionals whose income is only a tiny fraction of Romney’s. That disclosure also revealed a bank account in Switzerland and Romney family trusts in the tax havens of the Cayman Islands and Bermuda.

Mitt Romney is now flatly refusing to release any earlier tax returns. And he has taken an extension on his 2011 tax return, allowing him to delay filing and disclosure of that return until mid-October. That would allow just days before the November 6 general election to analyze any disclosed return in the final stretch of the campaign. He can also request an additional extension of time to file, which would delay his actual filing and any disclosure until after the November 6 election.

So what might Mitt Romney be hiding in refusing to fully disclose his tax returns? Additional tax returns may show that his 2010 tax return was indeed a “fluke”, giving the least outrageous picture of Romney’s wealth, income, and taxes. Tax returns for other years may disclose much bigger income taxed at much lower rates than reported in 2010, much greater use of tax shelters and loopholes of the kind his father refused to use, and additional investments of family wealth, not in the United States to fund jobs for American workers, but in foreign countries where the return on investment is greater, and investments can be more easily sheltered from taxes.

If elected President on November 6, Mitt Romney would be the wealthiest American ever elected to that office. Before we vote, the American people deserve to know how Mitt Romney acquired his wealth, and whether he paid his fair share of taxes along the way.

Mitt Romney has endorsed the Paul Ryan budget which advocates across-the-board tax cuts for all income categories including the top 1% of taxpayers like Romney himself. In refusing to follow his own father and President Obama’s example of full tax and income disclosure, Mitt Romney insults the intelligence of the American voter and disqualifies himself from the Presidency.