Washington’s hostile political factions have quickly taken up Fitch Ratings’ downgrade of U.S. government debt as a new weapon of political combat — highlighting in part why the firm stripped the U.S. of its top-tier credit rating.

Democrats and Republicans on Wednesday traded blame for the downgrade, with a group of hard-right conservatives promising to dig in during a looming spending fight that could shut down the federal government as soon as Oct. 1.

The bitter recriminations echoed the concerns raised by Fitch in announcing its decision after the close of financial markets on Tuesday. In a statement, Fitch cited an "erosion of governance relative to "AA" and "AAA" rated peers over the last two decades that has manifested in repeated debt limit standoffs and last-minute resolutions.”