For the moment, let's set aside the friction in U.S.-Israeli relations over Iran's nuclear program, which serves neither Washington nor Jerusalem.
Let's move beyond White House efforts to prevent an Israeli military strike before Election Day and its distancing from America's closest ally in the Middle East; beyond Tehran's accelerating progress on the nuclear front and its increasingly apocalyptic threats to Israel; and beyond Jerusalem's increasingly desperate warnings that its window for effective military action against Iran is fast closing.
Let's presume that Israel sits back before the election, President Barack Obama wins another term, and Iran proceeds apace.
Then, a second-term president who will be thinking about his legacy will face perhaps the defining foreign affairs issue of his tenure: Whether to use U.S. military force to prevent Iran from going nuclear.
That's because, at that point, Obama will face at least the following four realities:
First: More Iranian progress on its nuclear program that will make a successful Israeli strike (one that significantly cripples the program) more problematic.
The more progress that Iran makes, the larger the military strike needed to cripple the program will be.
Israel never had much hope of destroying Iran's nuclear program (though it surely could damage it severely and delay Tehran's achievement of a fully functioning nuclear weapons program for a year or two). But, with Iran clearing more hurdles to nuclear weaponry, Israel's ability to wreak havoc is shrinking.
The United States, of course, has the military capacity to go much further and wreak much more havoc. And, the more progress that Iran makes, the more that the burden of derailing it will fall to Washington.
The International Atomic Energy Agency recently reported that, over the summer, Iran doubled the number of centrifuges at its Fordow site near Qum, giving it three-quarters of the needed centrifuges to complete the site and feeding fears that Iran will be able to produce nuclear fuel at a protected site within a few months.
The IAEA also reported that Iran had cleaned up another site where, the agency suspects, Iran conducted tests related to nuclear weaponry, rendering its request to inspect the site largely moot.
Second: More evidence that U.S.-led efforts to convince Tehran to change course through sanctions and isolation will never work.
Iran's Holocaust-denying president, Mahmoud Ahmadinejad, admitted this week that four rounds of Security Council sanctions, buttressed by additional U.S. and European sanctions, are taking their toll on Iran's economy. Fine, but that has not derailed Tehran's steady nuclear progress.
U.S. leaders say Iran has never been more isolated diplomatically, but that didn't stop some 120 countries from sending heads of state and other top officials to last week's conference of the Non-Aligned Movement, which Tehran hosted. Nor did it stop U.S. officials from reportedly sending a back-channel message to Iran that they did not support an Israeli strike, which was apparently designed to prevent Iranian retaliation on U.S. forces in the region.
Washington continues to lead the effort to impose sanctions, and Tehran continues to march toward nuclear weaponry.
Third: The prospect of a regional nuclear arms race in the Middle East.
Though Israel is far more vocal about it, a nuclear Iran deeply worries Saudi Arabia, Jordan, and other regional states enough that many have announced plans to start their own nuclear programs.
The nations in question assure the world that their nuclear programs are civilian in nature, but no one believes them. Instead, they clearly will be designed to counter Iran's nuclear program.
All of that will put the world's most volatile region on a hair-trigger of potential nuclear confrontation -- with Iran, Arab states, and Israel eyeing one another constantly, warily, and vigilantly.
Fourth: Serious questions about whether containment or deterrence of a nuclear Iran can actually work.
Critics of any military strike contend that the U.S. can "contain" a nuclear Iran, as it contained a nuclear Soviet Union during the Cold War, and that Israel can "deter" Iran from attack through its threat of a nuclear counter-attack.
But Tehran isn't Moscow. While the latter was a traditional nation-state, the former is more of a revolutionary movement, many of whose leaders subscribe to an apocalyptic religious ideology that views end-of-world conflict with the West as not only likely, but welcome.
Besides, Tehran need not launch its own nuclear missile against Israel to start a frightening regional conflagration. It can slip a nuclear bomb to one of the terrorist groups that it sponsors, all of which are dedicated to Israel's destruction.
After Election Day, with time to stop Iran's nuclear progress running short, all eyes will focus on the man in the Oval Office. If that man is Obama, he will have to decide whether to fulfill his promise not to let Iran develop nuclear weapons, with military action of some sort likely the only viable option for doing so.
By then, he may be wishing that he had encouraged Israel to do its thing before the election.
Lawrence J. Haas, former communications director for Vice President Al Gore, is a senior fellow at the American Foreign Policy Council and author of "Sound the Trumpet: The United States and Human Rights Promotion" (just out from Rowman & Littlefield).