IN October 1962, the United States discovered that Russian warships had installed nuclear missiles in Cuba. The result was the Cold War's most dangerous crisis until the Russians backed down. This November, 46 years later, Russian warships will be back in those same Caribbean waters - this time at the invitation of South America's most dangerous dictator, Hugo Chavez of Venezuela, for joint exercises with his navy.

No one expects this to be a crisis of 1962 proportions. Venezuela's navy packs less wallop than the New York Yacht Club, and the Russian fleet is a shadow of its Cold War self. Only four ships will be going to Venezuela. State Department spokesman Sean McCormack quipped the wonder is the Russians "can find a few ships that can make it that far."

But don't be fooled by the bravado. Small though they are, these exercises are a stark challenge to US interests in South America and the Caribbean. They mark a major step in Chavez's bid to become the leading power in the southern Western Hemisphere. They also put the seal on Russia's aggressive re-emergence on the international scene both in Eastern Europe and Asia, and now in the Western Hemisphere.

Unlike in 1962, no nuclear weapons are coming to the party (at least, as far as we know). But the lead Russian ship, the nuclear-powered 19,000 ton cruiser Peter the Great, is one of the largest and deadliest missile cruisers afloat. It can deliver a volley of 20 500-kiloton nuke warheads with its Granit long-range missile system. Pravda reports that Russian strategic bombers will also be free to use Venezuelan airfields during the exercise.

No aircraft carriers are slated to take part. But Vladimir Putin will be pouring his petro rubles into building a new 50,000-ton carrier in 2010, as Russia's navy prepares for a glorious new era of projecting power around the world. Oil-rich Venezuela has been conducting a similar military buildup - ostensibly to defend himself against "Yanqi imperialism," in fact to intimidate its neighbors.

It's no coincidence that Chavez has used most of Venezuela's weapons budget to buy planes, submarines and missiles from Russia, including a bevy of SU-35 fighter jets. These two countries see a clear convergence of interests. In July, Chavez even went to Moscow to sign an alianza estrategica (strategic alliance) with Putin and Russian President Dmitry Medvedev, openly directed against the United States.

Both countries see fossil-fuel revenues as the key to their prosperity and power, as does the third power in this emerging petropower axis, Iran. All want monopolistic control over the oil and natural-gas resources in their respective regions.

In Iran's case, that means getting nukes in order to dominate the Persian Gulf, the world's lifeline for access to Middle East oil. For Putin, it means gaining control over Georgia and its vital oil pipeline. And for Chavez, the key to regional dominance has been building up Marxist allies in natural resource-rich neighbors like Bolivia and Ecuador.

All three regimes also recognize that the United States is the one power with the will and capacity to stand in their way. If, in these next eight weeks, Chavez can force the United States to acquiesce to his new strategic ties to Russia, with our navy standing helplessly by as Venezuelan and Russian warplanes and ships practice crushing a mock US "invasion" for the benefit of the world media, then he'll be one step closer to making the Caribbean a Venezuelan lake - and Putin will be one step closer to making Russia a player again in the Western Hemisphere.

The Russian Defense Ministry dismissed a July report in the newspaper Izvestia that the Russian Air Force hopes to get permission from Raoul Castro to base long-range bombers in Cuba. All in all, however, Russia is telling Latin America: We're back and we're not going to let the US push us out again.

The end of this summer has brought the end of many things. Wall Street came to an end last week, with the financial meltdown. The Bush Doctrine came to an end on Tuesday, with President Bush's lackluster speech at the United Nations endorsing multilateral "diplomacy" instead of firm action for curbing rogue states. In a month or two, we will learn if the Monroe Doctrine is headed the same way.