When you consider how much the existence of a few questionable North Korean nuclear weapons has frightened the world, and how most of civilization seems to agree that Iran should be blocked from having even one atomic bomb, it seems logical to conclude that the United States and Russia could remain global powers even if they significantly reduced their own nuclear arsenals.

Thus the welcome news the other day that U. S. President Obama and Russian President Dmitry Medvedev have agreed to cut their nuclear stockpiles by as much as a third as they continue to talk about both U. S. missile defense plans and a reduction in the limits on missiles and bombers.

The old habit of talking about arms limitations and reductions remains the most effective, because it is the most familiar, way to get our folks talking to theirs. And what is important is that our leaders never stop talking to their leaders.

And not just about each other.

That’s also what happened in Moscow this past week. A deal was struck that will allow the United States and NATO to fly through Russian airspace as they move troops and equipment to Afghanistan. That will save both time and an estimated $100 million a year in fuel and operating costs.

Of course, such a deal also could be revoked, a fact that gives Russian leaders a little more leverage than may be healthy for our side. And it also risks a situation where U. S. forces, trying to win Afghan hearts and minds, will be tagged as allies of the Russians, whose name still is mud to a great many Afghans after the long Soviet-era debacle there.

The two leaders also agreed that the nuclear programs in Iran and North Korea are troubling. The fact that they did not seem to come up with a joint solution to those matters says less about the U. S.-Russian relationship than about the fact that both situations will prove difficult to solve.

At least they were willing to set an example. Under the terms of the agreement sketched out in Moscow, a deal said to have been the personal breakthrough reached by the two top leaders, the next phase of the 1991 START (Strategic Arms Reduction Treaty) process would see the ceiling on the number of nuclear warheads each side can have lowered from the current 2,200 to as few as 1,500.

Considering how many people could be killed by each of those warheads, even the lowered number would still be many times more firepower than either nation needs to remain a force to be reckoned with—certainly not a country to be picked on by its neighbors and rivals.

Which is why countries with nuclear weapons need to keep talking to other countries with nuclear weapons. Because the day someone is seriously tempted to actually use one of those shatterers of worlds, we all lose.