“For a warning about America’s fiscal future,” said The Wall Street Journal in an editorial, look at Thursday’s move by Standard & Poor’s to downgrade Britain’s credit outlook, putting its topnotch AAA rating at risk. “Humiliation aside,” a downgrade would hurt Britain by raising public borrowing costs. The U.S. might want to keep this in mind as it follows the U.K. down the path of “out-of-control spending.”

America’s ballooning deficits are already hurting its borrowing capacity, said Mark Gilbert in Bloomberg. But the U.S. isn’t alone: Arguably, no government deserves “a top credit grade in the current financial climate.” Downgrading the U.S. to a “very strong” AA, from its “extremely strong” AAA, seems appropriate, if the rating agencies aren’t “too cowardly” to follow through.

With their credibility in the toilet, “rating agencies don’t matter anymore,” said Felix Salmon in Reuters. Investors buy U.S. Treasurys because they’re liquid and safe, not because S&P rates them AAA. And they’ll stay AAA so long as they have the lowest yields in the dollar-denominated world—if S&P cuts America’s credit rating, it will be a “lagging indicator.”