After a painfully wobbly response to a debate question regarding whether he would release his tax returns, Mitt Romney has relented and said he would release his 2011 tax return once it was filed in April.

Why should this be considered full disclosure?

There could be lots of things from his past tax returns which would be quite illuminating in the debate over our tax code.

For example, McClatchy notes that “because [Romney] owns homes in numerous states, he is likely to take tax deductions for property taxes and state taxes.”

But Romney sold two of his giant mansions recently. When his real estate portfolio was fatter, that would have driven his effective federal tax rate down.

Romney also may have exploited loopholes, particularly with offshore investments, as Reuters reported:

His tax returns could shed light on how Romney and Bain use offshore strategies to avoid taxes, said Daniel Berman, a former U.S. Treasury deputy international tax counsel and now director of tax at Boston University’s graduate tax program.

Bain funds in which Romney is invested are scattered from Delaware to the Cayman Islands and Bermuda, Ireland and Hong Kong, according to a Reuters analysis of securities filings.

“Certain interests in foreign investment structures would have to be reported on attachments to his return,” Berman said.

On capital gains, Romney’s tax returns would not reveal any gains that he has not yet realized, even though those gains would be easy for him to lock in at any time, Berman said.

Perhaps Romney was able to extricate himself from these tax loopholes for the current tax year, in hopes of avoiding a major debate over unfair tax rules.

But Romney is likely Exhibit A in the debate over whether our current tax code raises adequate funds to service the government the people demand, and whether it raises those funds fairly.

And if Romney really believes — as his proposals suggest — the only thing wrong with the tax code is that it taxes the wealthy and capital gains too much, then he should be happy to show us all of his tax returns as an example why that is the case.

Why hold back? Please show us the burdens you and your fellow job creators have been suffering all these years, so we can make the Bush tax cuts permanent, slash corporate taxes and abolish the estate tax right away.