Something bad always happens to the traditional tragic hero. That’s why Republican U.S. Sen. Tom Cotton of Arkansas is unlikely to be thrilled to get that label in Victor Davis Hanson‘s latest National Review Online column.

What Cotton and the senators have done is not criminal or stupid, but valuable both for the country and — ironically — for the Obama administration.

Obama is already mischaracterizing the letter to use it as a wedge with the Iranians. He seems to be reminding them that he is the only thing standing between them and the anti-Iranian hardliners in the U.S. senate. If Obama somehow manages to scare the Iranians into a treaty, he surely will not credit the senators for allowing him the leverage to play good cop to Senator Cotton’s bad cop.

More likely, the Munich-like agreement will fail in the face of outrageous Iranian demands and an even more outraged American public.

When it does, Obama will then blame Cotton and his Republican colleagues for undermining his doomed efforts. Such scapegoating is now old hat for Obama, who has blamed factors ranging from George W. Bush to tsunamis for his foreign policy and domestic failures.

Republicans, Democrats, and all Americans should thank Cotton for reminding the Iranians that under the U.S. Constitution, the Senate must ratify treaties with foreign powers. Cotton will get no credit if the Iranians get worried over his letter, relent and offer needed concessions.

But Cotton will endure plenty of blame if Iranian negotiators walk away in fury because a skeptical U.S. Senate would have to approve any sweetheart deal that they pulled over on Obama.