Officials reasons given will be the political confusion surrounding the process of raising the debt ceiling, and lack of confidence that the political system will be able to agree to more deficit reduction. A source says Republicans saying that they refuse to accept any tax increases as part of a larger deal will be part of the reason cited. end quote.
From an accounting and business point of view Republicans refusing any new taxes are helping Reduce S&P's credit rating of the U.S. from AAA+ to either AAA or AA. Though I understand Tea Party and Conservative Republicans tax stance, the pragmatic reality is that it was a major factor in losing our AAA+ credit rating from S&P. find more articles on this below.