In 2006, North Korea detonated a nuclear weapon and began testing missiles to deliver a warhead — tests that continue to this day. Despite the best efforts of two U.S. presidents — Bill Clinton through direct talks, and George W. Bush through multilateral negotiations — the effort to prevent North Korea from “going nuclear” failed.

North Korea became the ninth nation with nuclear weapons, joining the five permanent U.N. Security Council members — the United States, Britain, France, Russia and China — and the three states that previously built nuclear weapons outside the Non-Proliferation Treaty — India, Pakistan and Israel. North Korea is estimated to have 10 nuclear weapons.

This recent history is highly relevant to the current debate over Iran, but rarely mentioned.

Where Clinton and Bush failed, Barack Obama succeeded. We have a comprehensive, verifiable, enforceable agreement to prevent Iran from becoming the 10th nuclear state. If our politics were normal, we’d be celebrating a historic achievement, with congressmen singing its praises and proclaiming a collective, “Whew, that was close.”

But our politics is not normal, and the pundits’ question is whether President Obama can secure enough votes from Senate Democrats to block a resolution of disapproval (he can.) It’s the wrong question. We should be asking why anyone would vote no.

Critics say the agreement isn’t perfect, and it’s not. No agreement between adversaries ever is. Yet the Iran agreement is far stronger than we had reason to hope for even a few months ago. Iran has committed to handing over 98 percent of its uranium stocks, and in so doing will increase the time needed to build nuclear weapons from two months — where it stands if we reject the agreement — to at least one year.

Critics rejoin that we can’t have “instant” inspections, but we don’t need them. The International Atomic Energy Agency — respected, well-funded, well-run — says it can detect any cheating with a 24-day notice requirement. Unlike the four newest nuclear states, Iran signed the Non-Proliferation Treaty and has had IAEA inspections, another fact critics miss.

The IAEA would have discovered the non-existence of Iraq’s nuclear program in 2002 as well, if President Bush had given inspectors enough time — rather than heedlessly invading the following January — while nullifying Condoleeza Rice’s claim that a “mushroom cloud” might appear over Israel.

But what about the “mortal threat” to Israel from Iran, the supposed reason we must reject the treaty and allow Iran to quickly build a nuclear weapon? Putting aside endless rhetoric from Israeli Prime Minister Benjamin Netanyahu and his close congressional allies, here’s the salient fact: Israel is believed to have 80 nuclear weapons. Iran has none. That’s called deterrence.

Critics’ fantasies multiply from there. The agreement is unacceptable, they say, because it allows Iran to pursue terrorism (nothing stopping it now), that it doesn’t free American captives (negotiations were only about non-proliferation), that it provides Obama a victory (oops, don’t mention that.)

The biggest fantasy is that we can scuttle the agreement and retain sanctions. After 35 years of “death to America” politics, Iran has agreed to rejoin the international community. If we say no, its only logical course is to build nuclear weapons and avoid Saddam Hussein’s fate.

Contrary to popular stereotype, “death to America” is fading even in Iran. The under-30s, the majority, have little interest in this conflict, and most would prefer a prosperous, westernized future. The rupture in the Iran-American alliance caused by the shah’s fall in 1979 could finally be repaired, and we would no longer be dependent on the terrorist-funding Kingdom of Saudi Arabia to guarantee our interests.

Most senators are still making up their minds. Twenty Democrats have pledged support, while Charles Schumer of New York cravenly announced opposition, forfeiting any chance of becoming Senate leader next year. Here, Schumer represents Netanyahu and the Israel lobby, not American Jews, who support the agreement by larger margins than most Americans.

Sen. Angus King has announced support, and appeared Wednesday with George Mitchell, who once held this Senate seat, to explain, carefully and patiently, why the agreement is in the national interest.

Maine’s other senator, Susan Collins, has said nothing, and may not until the Senate reconvenes on Sept. 8. She could play a pivotal role as the first Republican to declare independence from the mindless partisanship now dominating Washington.

For it will make a huge difference whether the Senate — our traditional forum for debating world affairs — actually endorses this historic agreement, or simply fails to veto it. A new era is coming in the Middle East. The only question is whether America will lead it.

Douglas Rooks has covered the State House for 30 years. Email at drooks@tds.net.