COLUMBUS, Ohio — Will the international sanctions currently in place against Iran keep it from developing nuclear weapons? Is Iran likely to develop nuclear weapons if left to its own devices?

The world’s major powers are playing a delicate diplomatic game to get Iran to prove it is not developing nuclear weapons. Sanctions imposed six months ago on Iran’s central bank, and on Iran’s sale of oil, have sent the Iranian economy into a tailspin. More sanctions are scheduled to take effect in July.

The basis for this pressure on Iran is clouded in legal and moral ambiguity. Iran is a party to the 1968 Nuclear Non-Proliferation Treaty, which says that nuclear weapons should not be acquired by countries that do not already have them. Nuclear technology for peaceful purposes is fine, but is subject to inspection by the International Atomic Energy Agency. Iran allows inspection, but not to every site the inspectors want to visit.

Under the treaty, existing nuclear powers are supposed to negotiate towards nuclear disarmament. But they have dallied. So the powers that developed nuclear weaponry early on are telling Iran it may not do the same.

Iran is enriching uranium to a 20 percent level, and uranium at that level can easily be enriched further, to a level needed for weapons. Iranian officials are quick to point out that enriching uranium is not a violation of the Treaty. Iran says it has no plans to build nuclear weapons, and there is no firm evidence that it is moving that way.

To heighten the ambiguity of the situation, a regional state perennially at odds with Iran, namely Israel, already possesses nuclear weapons, and in condition to be launched at any moment.

This gives Iran a perfect reason to acquire them — as a deterrent to Israel. The major impetus for any state to acquire nuclear weapons is to keep an adversary from using them. The Western powers do not pressure Israel to divest of its nuclear weapons. They barely speak in public of the existence of Israel’s nuclear stocks.

So while the Obama administration portrays its efforts against the development of nuclear weapons by Iran as keeping the world safe, the uneven pursuit of a nuclear-weapon-free world clouds its moral authority.

A related criticism is that the United States is simply doing Israel’s bidding. Israeli Prime Minister Benjamin Netanyahu delights in discussing the “existential threat” that a nuclear Iran would pose to Israel.

A focus on Iran gives Netanyahu the moral high ground, which Israel desperately needs, while it is routinely excoriated in international institutions for taking more and more Palestinian land for settlements.

Iran may perceive the sanctions being aimed less at its nuclear program than at regime change. If that is Iran’s perception, as some analysts suggest it to be, then the sanctions are not likely to convince Iran to make changes in its nuclear policy. The Western powers have not hid their dislike for the current Iranian government.

A six-nation group — the five permanent members of the U.N. Security Council plus Germany — is negotiating with Iran about its nuclear program. But the six are not united.

While the Western powers advocate tough sanctions, Russia is calling for an immediate easing of them in preparation for the next round of talks, to be held shortly in Moscow. Russia has denounced new restrictions approved a few days ago by the U.S. Senate, which would further tighten existing sanctions on Iran’s banks and oil exports.

Iran meanwhile is in apparently serious talks with the IAEA to allow inspection of military sites hitherto closed to inspectors.

IAEA Director-General, Yukiya Amano, professes optimism that Iran may agree. That access could help determine Iran’s intentions. Easing sanctions might just show the West’s good faith and help resolve the nuclear standoff.

• Quigley is a professor of law at Ohio State University.