Oil prices shed 1% in Thursday morning trading over American debt and the prospects for a historic default, despite gains on Wednesday driven by demand optimism in the U.S. market. Bloomberg’s take on this is that Wall Street is afraid of what it calculates as a potential $1-trillion aftershock for the economy if the debt ceiling is not resolved.  On Thursday at 10:38 a.m. EST, Brent crude was trading down 1% at $76.19, down 77 cents on the day, while WTI was down 0.85% at $72.21, down 62 cents on the day. U.S. President Joe Biden is…