Last week, the Russian news agency ITAR-TASS reported that North Korean leader Kim Jong Un and Russian President Vladmir Putin "regularly exchange messages." Cold War allies Russia and North Korea have re-ignited ties in recent months, on the surface talking about economic issues. In reality, they're likely discussing much more.

This is bad and alarming news. Russia, which would have little reason to rein in the North's outrageous behavior, could eclipse more moderate China as the isolated country's patron. This would be a step backward in terms of the security of Northeast Asia — and the United States.

During the Cold War, North Korea was well within the Soviet sphere of influence. North Korean leader Kim Il Sung, current leader Kim Jong Il's grandfather, was a steadfast Soviet ally. In return, he received lavish arms shipments and economic aid. Most of North Korea's military hardware is so old it dates to this era.

The collapse of the Soviet Union in 1991 meant an abrupt end of Soviet support for Kim Il Sung. Faced with a rapidly declining country and military, his son and successor, Kim Jong Il, deepened ties to China and developed nuclear weapons to buttress his defenses.

His son, Kim Jong Un, appears to be turning to the Russians again.

There are good reasons why Russia is expanding ties with North Korea. As the TASS report states, there are economic opportunities to be had. Russia would like to sell electricity and natural gas to South Korea, and both will have to go through North Korea. North Korea also has trillions in mineral wealth it needs capital to exploit.

There are also bad reasons.

Russian President Vladimir Putin is bent on restoring not only the old Soviet Union's borders, but its sphere of influence and client states. States such as East Germany and North Korea were particularly useful in they insulated the Soviet Union from another World War II-style attack.

If you view Russia as continually under threat, as Putin and his allies do, you want the protection of those satellite nations back.

Russia is also looking for an Asian provocateur. Russia's current ambition is centered on the Ukraine. An expansionist Russia could very much use an ally in Asia that preoccupied the United States, Japan, and South Korea with its sporadic, violent outbursts.

In that respect, North Korea fits the bill perfectly.

North Korea has been an embarrassment for China, which has attempted to embrace its neighbor in the hopes it could moderate its behavior. That has not happened. Chinese officials are reported to be exasperated with the Kim regime. North Korea came under criticism in China's state press, China supported reunification talks proposed by South Korean President Park Gyeun-Hye, and state media openly speculated that China was abandoning the country.

Instead of being reined in, North Korea branded China as a "turncoat and our enemy." It was around then that Kim Jong Un apparently decided to look for a new patron.

As Kim Jong Un's new patron, Russia would be no such moderating influence. Russia may even encourage North Korea to commit further attacks, like the 2010 sinking of a South Korean Navy ship and artillery bombardment of a South Korean island, in order to draw attention to itself and away from Russian adventures in Europe. And it would provide Kim Jong Un with the tools to do so.

Russia assistance to North Korea would be limited, but crucial. North Korea would be interested in nuclear and rocket technology, to improve its nuclear weapons and put the United States within range. That is not something that Russia will be willing to do.

Russia, on the other hand, would be willing to update North Korea's conventional arsenal with fighter and attack planes, drones, armored vehicles, and artillery. Most of North Korea's military equipment is wasting away, becoming obsolete and unserviceable. North Korea's Air Force and Navy have suffered a number of high profile accidents. Russian military aid would go a long way toward reversing that trend — and increasing American attention on the tiny country.

North Korea may be flirting with Russia, but don't count China out. China has extensive links with North Korea's economy that make relations with it indispensable — no matter how much it is publicly branded a turncoat and enemy. In a sign that Beijing realizes its influence in North Korea is at risk, China recently delivered an entire year's worth of civil aviation fuel to Pyongyang — a shipment that was canceled the year before.

It's an odd contest: win the world's worst friend, North Korea. No matter who wins, the North Korean people won't be any better off.