Like the bone-chilling Siberian winter winds, the bad news just keeps howling out of Mother Russia these days.

Following on the heels of less-than-free-and-fair parliamentary elections, last week Russia concluded a deal with Iran to finish construction of the nuclear reactor at Bushehr early next year.

And this week, Russia delivered a year's worth of nuclear fuel - 82 tons - for Bushehr, broadening and deepening Tehran's atomic aptitude and its potential for joining the once exclusive nuclear-weapons club.

Of course, the Russians say there's no reason to worry because they have written assurances from the Iranians the fuel won't go for anything but power generation at the plant - and will be returned to Russia after it's "spent."

The Kremlin's foreign ministry also assures us that the nuclear fuel, while in Iran, will be under the "control and guarantee" of the UN nuclear watchdog, the International Atomic Energy Agency. (Yes, the same agency Iran has hoodwinked for over 20 years.)

Both Moscow and Washington tried to put a happy face on it, saying the Kremlin's decision should provide more incentive to Iran to stop enriching uranium with those 3,000 or so A.Q. Khan-designed centrifuges they're spinning 24/7/365. (The Iranian response? "Fat chance.")

The Russians' decision is a fateful one - if they really complete and fuel the Bushehr reactor this time. They've halted work before, supposedly because of payment problems on the Iranian side. Clearly, Iran has met Russia's price - whatever that was.

But, ultimately, an Iranian nuclear-weapons breakout isn't in Russia's interest. Another nuclear power in the neighborhood weakens the currency of being a nuclear power in the first place, undermining Russian influence.

And Iran could wind up threatening not only Russia's southern flank, but the heart of the motherland, too, with the nuclear-capable ballistic missiles it's developing.

Russia also has been courting Middle Eastern states lately, trying to increase the Kremlin's influence. It isn't going to win friends among the Arabs or the Israelis by helping out the Iranians with any nuclear program. So, what's really behind Moscow's decision?

First, Russian President Vladimir Putin has said he doesn't believe Tehran has a nuclear-weapons program. The recent US National Intelligence Estimate (NIE) - stating that Iran halted its Iran's nuclear-weapons program in 2003 - means that Washington can't grouse too much.

Plus, the Russians are still hopping mad about the notion of American missile defenses based in Poland and the Czech Republic. They may be hoping that the United States will trade the missile shield for an easing of Russian support for the Iranian nuclear program.

(Of course, the Russian decision to help Iran's program is a heckuva reason to go ahead with the Eastern Europe-based defense - it's aimed at thwarting the Iranian missile threat.)

Moreover, the Russians likely see a commercial nuclear relationship with Iran as highly profitable. Tehran says it wants to build a bunch of nuclear power stations - not bad work for the Russian nuclear industry at $1 billion a piece.

So if the Iranians actually agree to suspend uranium enrichment - just play along for a while - and to cooperate with an international consortium that would provide, retrieve and dispose of reactor fuel, the Russians could make a bundle.

Finally, Russia, seeing the United States as an international competitor for influence, doesn't mind keeping us off balance in the Middle East by playing the Iran card when it makes sense for the Kremlin to do so.

The Russians see Iran, the region's rising power and an energy giant, as a possible partner on several fronts, including cooperation on Caspian Sea energy and the formation of an OPEC-like natural-gas cartel.

Sure, the Kremlin has called for Iran to stop uranium enrichment, encouraging Tehran to cooperate with the IAEA and live within its commitments under the Nuclear Nonproliferation Treaty.

But this is nothing more than lip service: the Iranians are still enriching uranium - while the Russians are delivering fuel and restarting construction on Bushehr. And that, in the end, will undermine Russian security as well as ours.

Peter Brookes is a Heritage Foundation senior fellow and former US deputy assistant secretary of defense.