WASHINGTON (Reuters) - New Jersey Governor Chris Christie, a key ally of Republican presidential front-runner Mitt Romney, on Wednesday joined Romney's rivals in urging the candidate to release his income tax forms after he said he pays roughly a 15 percent tax rate.
"Let's get all of the facts out there. See what the tax returns say," Christie told MSNBC's program "Morning Joe," although he downplayed that the forms would reveal much and that all the attention would probably be "much ado about nothing."
On Tuesday, Romney told reporters that most of his income stems from investments, placing him at the 15 percent rate - a rate much lower than what most Americans pay. He has said he would not release his tax returns until April.
Romney's Republican rivals have been eager to paint the former private equity executive at Bain Capital LLC and Massachusetts governor as out-of-touch with ordinary voters amid a slow economic recovery and have pounced on the tax issue.
"What I would say to Governor Romney is: if you have tax returns to put out, you should put them out. You should put them out sooner rather than later because it's always better to have full disclosure, especially if you're the frontrunner," Christie said on NBC's program "Today."
Christie, mentioned as a possible vice presidential running mate for Romney, has been actively campaigning for the former Massachusetts governor, making appearances in New Hampshire and Iowa, the first two states to hold nominating contests.
Romney is leading the pack in the state-by-state race for the Republican Party's presidential nomination to face Democratic President Barack Obama on November 6. Saturday's Republican South Carolina primary is the next contest in the race.
Former House of Representatives Speaker Newt Gingrich and Texas Governor Rick Perry have suggested that Romney may be hiding something in not releasing his tax forms.
Some tax analysts have also said it could shed light on Romney's work at the helm of Bain Capital that could give political ammunition to rivals.
A Wall Street Journal editorial on Wednesday called on Romney to use his returns as a platform to call for a simplified U.S. tax code.
"Mr. Romney could use the opportunity to make the moral and practical case for lower rates and fewer loopholes," the Wall Street Journal said.
Romney, whose estimated net worth is $270 million, is one of the wealthiest people to ever run for U.S. president.
Christie said he would not rule out serving as the Republican vice presidential candidate but added that he was planning to continue serving as New Jersey's governor and has had "zero" discussions with Romney about the job.
"If you're a betting guy, I would bet on me being governor of New Jersey after November 2012. But I think it's rude and wrong to say you wouldn't do something that you haven't been asked to do, and I haven't been asked to do it," Christie told the "Today" show.
(Reporting By Susan Heavey; editing by Mary Milliken and Will Dunham)