Who believes the government in Iran has had an epiphany and suddenly wants to shed its rogue-nation status and sing Kumbaya with the rest of the world?

Not us. And certainly not the harsh critics of the nuclear weapons deal negotiated by Secretary of State John Kerry.

But something has changed. The willingness of President Hassan Rouhani to engage in talks with the United States and five other nations on nuclear weapons is a breakthrough in itself. It brings at least some hope of averting what had looked like inevitable war with Iran to take out its nuclear capabilities before it can use them.

This pact, which lasts only six months, will be judged a success only if it is a down payment on a comprehensive one.

And if Iran wants to avoid that attack from the West -- a more likely motivator for Rouhani than a Kumbaya moment -- it knows it has to get back to the table pronto to show a doubtful world it's serious about going un-rogue.

The agreement ostensibly slows progress on Iran's nuclear program in exchange for lifting about $7 billion worth of economic sanctions that have been crippling its economy.

President Barack Obama said it "halted" progress on Iran's nuclear efforts, but that is a stretch. It does not require Iran to close its plutonium reactor at Arak, nor to give inspectors unfettered access to such suspect sites as Parchin. Iran does not have to give up its nearly 10,000 enrichment centrifuges or even stop using them, let alone cede control of its enrichment stockpiles.

Some critics argue that the agreement will boost Iran's flagging economy and buy time for the government to continue developing weapons. But is having no agreement any better? A poor economy hasn't stopped Iran from pursuing nuclear progress until now.

Our biggest worries about the pact are geopolitical. Israel and Saudi Arabia are upset that it does not touch Iran's nuclear infrastructure. Both countries fear nuclear capability would allow Iran to dominate the political environment in the Middle East.

In the worst case, Israel, feeling betrayed by the United States and other Western nations, might launch a pre-emptive attack against Iran. It wouldn't be the first time. And there is mounting evidence that Saudi Arabia might join Israel, or at least assist in its attack. So much for buying a war-free six months.

Next diplomatic test: The U.S. has to exert all -- really, all -- of its influence to restrain these unlikely allies.

The United States has to learn to achieve its ends more often through diplomacy rather than launching wars. We have to stay strong militarily, but we cannot look at war as a reasonable way to solve problems.

Yes, this pact could turn out to be, as critics believe, merely a stalling tactic by Iran rather than the beginning of real progress. But it's worth a six-month trial to find out.

-- Contra Costa Times, Digital First Media