WASHINGTON -- Despite a bipartisan desire to help U.S. business compete better against foreign rivals with lower taxes, the window appears to be closing for a comprehensive revamp of how business is taxed.The New Year's deal to avoid the "fiscal cliff" averted a potential economic catastrophe, but it also changed the equation on which calls for overhauling the corporate tax code were based.As recently as 2008, about 12 percent of federal revenue came from corporate taxes, according to the nonpartisan Congressional Budget Office.Most corporations don't pay the 35 percent rate -- the highest in the developed world except for Japan -- but take advantage of tax breaks to bring that down to an average of about 25 percent.During his 2012 campaign, President Barack Obama supported lowering the corporate tax to 28 percent. His vanquished rival, Mitt Romney, wanted it down to 25 percent.But those were part of a vision for a broader tax revamp."The enthusiasm for moving that rate down is going to be nonexistent by the administration. And moving tax reform with no help from the administration is going to be very difficult," said Catherine Schultz, vice president for tax policy at the National Foreign Trade Council, a lobby for multinational corporations. "There is not a lot of incentive for the Obama administration to move forward on comprehensive tax reform."The White House didn't reply to requests for comment, but Obama briefly mentioned the tax code in his inaugural address.Before the New Year's budget deal, updating the corporate tax code was a bargaining chip to dangle in front of Republicans in what many thought might be the first comprehensive overhaul of taxation since 1986.But that depended on the income tax cuts that were expiring Dec. 31 being extended another year.