With diplomats like ours, why shouldn't the world smell weakness?

Post-America's UN ambassador Samantha Powers is concerned about our nation's loss of cred on the world stage should Congress 86 the Iran deal:

First, if the United States rejects this deal, we would instantly isolate ourselves from the countries that spent nearly two years working with American negotiators to hammer out its toughest provisions. Those partners believe that this is a sound deal—with a rigorous set of inspection measures that would allow us to know if Iran is not playing by the rules. And those countries have been very clear that they are not prepared to walk away from this deal to try to secure different terms. So if we walk away, there is no diplomatic door number two. No do over. No rewrite of the deal on the table. We would go from a situation in which Iran is isolated to one in which the United States is isolated. That would not be ideal under any circumstances, but it would be particularly damaging in a context in which Iran continues to pose a profound threat to international peace and security, against which global unity and pressure will be critical. 

Second, well beyond the consequences vis-a-vis Iran itself, rejecting this deal would likely undermine our ability to use sanctions in other circumstances. At the UN I routinely encounter countries that do not want to impose sanctions or even to enforce those already on the books. The hard-line sanctions skeptics have their own self-interested reasons for opposing sanctions, but they ground their opposition in claims that America uses sanctions to inflict punishment for punishment’s sake. In response, I tell foreign diplomats that sanctions are not an end in themselves, but a means of marrying coercive measures with diplomacy to try to change behavior—whether that behavior threatens international security or inflicts widespread human suffering. And I tell those diplomats that when diplomatic paths seem to emerge, America will pursue them, and we will ease the pressure if the grounds for imposing sanctions are addressed. 

In the case of Iran, the United States persuaded other countries to apply pressure for a purpose—in order to secure significant, long-term constraints that would cut off all of Iran’s pathways to a nuclear weapon. If we move the goalpost now—arguing, for example, that there should not be sanctions relief until Iran stops supporting terrorist proxies or until it permanently gives up nuclear enrichment for peaceful purposes—we would give detractors a powerful tool to try to obstruct our future efforts on issues unrelated to Iran. Our efforts to reach this deal have affirmed the view of the United States as a tough but principled leader; rejecting it would be read in many quarters as a superpower intent on inflicting pain for its own sake. 

A few indications of her world view stick out like sore thumbs here. There's her ironclad confidence that sanctions snapback would  would be a snap:

 . . . businesses that had already signed new contracts in Iran . . . would have to phase out their contracts or face penalties for violating sanction

Then there's her tacit acknowledgement that this deal allows Iran to continue to foment terrorism.

Then there's her saddening belief that "shared values" rank higher with German, Turkish and Russian businesses - and the governments that give them the green light to sign deals with Tehran - than opportunity for lucrative commerce.

While . . . soft power is built in many ways, two of its most important sources are the belief among other countries’ leaders and publics that we share similar values, and that America delivers on its commitments.

Let's look at Russia in particular, since it is a rather unavoidable force among the nation-states that crafted this "deal." Does it really share our values, or believe that America delivers on its commitments?

The evidence suggests otherwise:

On September 5, 2014, Russian agents crossed into Estonia and kidnapped an Estonian security official. Last week, after a closed trial, Russia sentenced him to 15 years.

The reaction? The State Department issued a statement. The NATO secretary-general issued a tweet. Neither did anything. The European Union (reports the Wall Street Journal) said it was too early to discuss any possible action.

The timing of this brazen violation of NATO territory — two days after President Obama visited Estonia to symbolize America’s commitment to its security — is testimony to Vladimir Putin’s contempt for the American president. He knows Obama will do nothing. Why should he think otherwise?

Putin breaks the arms embargo to Iran by lifting the hold on selling it S-300 missiles. Obama responds by excusing him, saying it wasn’t technically illegal and adding, with a tip of the hat to Putin’s patience: “I’m frankly surprised that it held this long.”

Russia mousetraps Obama at the eleventh hour of the Iran negotiations, joining Iran in demanding that the conventional-weapons and ballistic-missile embargos be dropped. Obama caves.

Putin invades Ukraine, annexes Crimea, breaks two Minsk cease-fire agreements, and erases the Russia–Ukraine border. Obama’s response? Pinprick sanctions, empty threats, and a continuing refusal to supply Ukraine with defensive weaponry, lest he provoke Putin.

It's extremely difficult to take Powers seriously in light of the actual facts on the ground.

What most of the world sees is a patsy former superpower that will do nothing to prevent shortsighted opportunists from exploiting a situation that's going to be profitable in the short term, but, beyond that time frame, is going to wind up facilitating an apocalyptic scenario we can scarcely bear to contemplate.