To cite a line made famous by actor William Shatner, 'How big could Mitt Romney's failure to release 10-years' worth of U.S. income tax returns be?'

'Really big' -- as in it could ruin his chance for winning the U.S. presidency in 2012. Here's why:

A crisis management, inside-the-beltway axiom is, 'Get the worst information out first, as long as it is not catastrophically damaging.'   This is also known as 'worst first.'

'Worst First'...Unless

In other words, from a polling/public approval standpoint, historically, mainstream media coverage of scandals and problems demonstrates that if the action/evidence publicized is not an enormous mistake, the candidate/public official sustains the largest decrease in public approval in the initial period of the scandal, then he/she slowly recovers.  I.E., most scandal issues are firestorms that die-out quickly, if the worst information is released first.

On the other hand, if a candidate/public official does not admit the mistake, the controversy will often continue, with media coverage further decreasing his/her public approval, and often more damage is sustained than would occur if the candidate/public official had simply admitted the mistake and apologized -- sometimes resulting in a resignation, and/or a very low public approval rating that all-but-dooms one's election/re-election chances.

Does the U.S. income tax report issue of prospective Republican Party nominee Romney represent an issue that is 'catastrophically damaging'?  As long as there has not been an incontrovertible, major violation of U.S. tax law, it probably is not.

A minor tax filing mistake or an income categorization error is hardly enough to trigger a sustained plunge in Romney's public approval rating. The reason? Many Americans can identify with a tax filing error or an income category mistake because they're committed the error themselves.

By extension, if it's just a minor error, from an electoral standpoint Romney would be better off simply stating the error and/or releasing an adequate number of annual income tax reports: ideally, Romney should release the past 10 years; at minimum, four or five years.

If it's minor and Romney releases the reports, this issue will not cause him to lose any ground to President Barack Obama in what is currently a tight 2012 presidential race. According to the latest Gallup poll, conducted July 21-23, Obama leads Romney 46 percent to 45 percent -- a 1 percent margin that's within the poll's margin of error. In other words, the presidential race is about as close as it can be, and if the distribution holds through Election Day, Romney could be the winner.

However, if Romney doesn't release the U.S. income tax returns, the tax report issue will fester -- the cloud that Romney is hiding something, or that there is a dimension to his income tax report(s) that he is embarrassed to reveal, will become more imposing -- and voter support for him will likely decline.

Get The Information Out, And Put The Issue To Rest

Each presidential election cycle is different, but if history is any guide, it's in Romney's interest to release the tax forms now; again, as long as there's nothing in them that's catastrophically damaging.

For example, during the1984 presidential campaign, after questions arose about the couple's finances, Democratic Party Vice President Nominee Geraldine Ferraro, running with Presidential Nominee Walter Mondale, initially refused to release Ferraro's husband John Zaccaro's tax returns. Result: a political firestorm ensued, media coverage of their finance/tax issue multiplied, and the Mondale/Ferraro ticket took a substantial hit in the polls. A week after saying they would not, Ferraro and Zaccaro released the tax returns, and included in them was a notice of a payment of about $53,000 in back federal taxes, but from an electoral standpoint the public disclosure was too late. The damage was done: millions of voters had switched their support for the Mondale/Ferraro ticket to Reagan/Bush.  

To be sure, given the strong U.S. economy in 1984, Democratic challengers Mondale/Ferraro were not likely to defeat Republican incumbent President Ronald Reagan, but the tax scandal certainly decreased voter support for the Democrats and widened Reagan's margin of victory -- increasing the number House/Senate seats won by the GOP.  Moreover, the important is that had Ferraro released all of the returns at the outset, the Mondale/Ferraro ticket would have sustained less damage.

Transparency, Now

In sum, from an electoral standpoint the best thing Romney can do is release at least four to five annual income tax reports. If Romney does, and there's nothing catastrophic in them, the issue will likely fade from the public's attention.

If Romney doesn't release the reports, doubts will linger concerning what's in them, and Romney will likely lose votes, as a result - votes that could cost him the election.