During the debt-ceiling debacle, Washington pushed the United States economy close to an abyss. Now it is risking US-China relations.

Two months ago, Chinese officials were appalled by the US debt impasse. A month ago, Vice-President Joe Biden, after Washington's summer-long debt drama, sought to assure Beijing that "a successful China can make our country more prosperous, not less".

Now the Senate is weighing "whether to punish China for undervaluing its currency and taking away American jobs".