The not-so-secret secret is now out—Israel has U-boat submarines that can launch nuclear-tipped cruise missiles. The Israeli nuclear arsenal is a triad—it can launch nuclear war from American-built F-15s, the French-origin Jericho missile and German-built Dolphin-class U-boats. It has a survivable second-strike capability and can project power far beyond its immediate environment.

Der Spiegel, the German news magazine, broke the story after extensive interviews with German and Israeli sources. Long rumored to be nuclear-delivery systems, the underwater fleet Israel has acquired over two decades is now clearly nuclear equipped. The Israeli Navy has three operational Dolphins, a fourth will soon be operational; a fifth is under construction in Kiel; and a sixth has been ordered. Israel builds the cruise missiles that provide the delivery means for the nukes, so technically Germany is not engaging in nuclear matters. But Berlin knows what it is doing.

The Israeli press has picked up the story now that the foreign press has put it out. That is consistent with Israel's long-standing policy of not confirming its nuclear arsenal. The timing of the leak, though, is probably no coincidence, as tensions with Iran are building again. Israel may well be sending Iran a message that retaliation for an Israeli attack on Iran's nuclear facilities could lead to a dangerous escalation in which Israel holds the upper hand.

The U-boat story underscores a key fact about the Iranian nuclear threat. With or without nuclear weapons, Iran is outclassed and outgunned by Israel in both the conventional and nuclear balance of power. Israel has a far superior air force with the latest U.S. aircraft, whereas Iran's is equipped with 1960s’ antiques bought by the Shah. Iran is under a comprehensive UN arms embargo, so its military has no access to modern technology. Israel gets at least $3 billion in new equipment from America every year. Having been a nuclear power since 1968, Israel has dozens of bombs.

In short, Israel is the regional military superpower. The Arab Spring is demolishing the capabilities of Iran's key ally, Syria. Hezbollah is in danger of losing its Syrian backers, and Lebanon is in danger of slipping into another civil war exported from Damascus, which would keep Hezbollah preoccupied. The balance of power tilts decisively toward Israel, which is a success story of American diplomacy. Every president since JFK, who was the first to sell Israel advanced arms, has helped build Israel's edge. Washington has promised to maintain Israel's qualitative superiority over its enemies for decades. Now we know it got some help from Berlin as well.

Bruce Riedel is a senior fellow in the Saban Center for Middle East Policy at the Brookings Institution. A career CIA officer, he has advised four presidents on Middle East and South Asian issues in the White House on the staff of the NSC. He is author of The Search for Al-Qaeda (Brookings Institution Press, 2008) and Deadly Embrace: Pakistan, America and the Future of the Global Jihad (Brookings Institution Press, 2011).

Image: Israel Defense Forces