What a difference six months can make. In just half a year, U.S-Russian relations have risen from their a 15-year nadir, up through waning degrees of discomfort, all the way to the level of a genuine strategic partnership.

In August, many in American media, academia and government genuinely feared the resumption of the Cold War. In February, Russian and American diplomats forged an alliance that will prove critical to U.S. goals in Central Asia.

There are several potential explanations for the change: the advent of a new American administration, a rapidly decaying global economy, a shift in Russian strategy, or a combination of the three. Any way you cut it, the relatively painless rapprochement is indicative of an important truth. Despite the "Cold War" rhetoric that periodically intrudes in Western newspaper headlines and Muscovite speechifying, that conflict is long over ... and not likely to return.

Lowest of the lows

The brief but intense war between Russia and Georgia over the breakaway province of South Ossetia last August stoked long-dormant fears deep in the hearts of many of the American political elite. "With a little assistance from Russia and the Republic of Georgia ... we're bringing back the Cold War," wrote Los Angeles Times columnist Rosa Brooks.

"The end of history will be postponed, again," lamented conservative pundit George Will in the pages of The Washington Post. "Russia's military offensive into Georgia has shattered, perhaps irrevocably, the strategy of three successive presidential administrations to coax Russia into alliance with the West and integration into its institutions," The New York Times moaned.

Even some everyday Americans joined the hand-wringing, resurrecting decades-old attitudes about the United States' former Cold-War rival. "Regardless of who started the conflict between Russia and Georgia, Russia is taking their time to leave," Darryl Dunlap, a retired soldier, told Time. "If you've ever seen the dark shadow of old-world Communism before the [Berlin] wall fell, it's scary."

Official statements from the Bush Administration were more carefully worded -- but still quite extreme. "If Russia does not step back from its aggressive posture and actions in Georgia, the U.S.-Russian relationship could be adversely affected for years to come," warned Secretary of Defense Robert Gates.

Sure enough, in the aftermath of the South Ossetia conflict, a deep, albeit brief, chill settled over U.S.-Russian relations. Joint military training exercises dating back to the mid 1990s were canceled. While spokespeople for both governments issued foreboding statements, the U.S. and Russian militaries, once tentative partners, became rivals again, almost overnight.

The fighting in Georgia hadn‘t even ended before the Bush Administration began deploying aircraft and warships to the Georgia, moves that were hard to see as anything but deliberately provocative. American cargo planes helped transport Georgian troop reinforcements from Iraq, and later delivered humanitarian aid to the Georgian government.

U.S. Navy and Coast Guard ships hauled medicine, blankets and other aid to Georgia, challenging a Russian naval blockade to do so. With a the Navy destroyer McFaul keeping watch, the Coast Guard cutter Dallas, under command of Captain Robert Wagner, sailed past a Russian frigate to enter the port of Batumi. The Russian sailors carefully examined Dallas to "see what we had on our deck," Wagner said. The encounter was tense but "professional," Wagner said.

But Russia didn't see America's actions that way. Warships were not the "best way" to deliver humanitarian aid to Georgia, Russian Foreign Ministry official Andrei Nesterenko told CNN. In retaliation, in September two Russian warships sailed to Venezuela to train with the navies of Latin America's emerging "pro-Russia" bloc. "Go ahead and squeal, Yankees," Venezuelan President Hugo Chavez said when he announced the exercise. Russian nuclear-capable bombers also deployed to South America for exercises.

Missiles make me crazy

Tensions only mounted as the Pentagon proceeded with controversial plans to build ballistic-missile defenses in Poland. The defenses comprised interceptor missiles officially intended to stop attacks aimed at the U.S. mainland from Iran. But Moscow read the defenses as deliberate undermining of decades of carefully constructed treaty relationships aimed at creating nuclear parity between the U.S. and Russia.

"Poland is making itself a target. Such targets are destroyed as a first priority." Russian General Anatoly Nogovits warned in August after Poland agreed to allow the U.S. to build its interceptor sites.

America's response? "When you threaten Poland, you perhaps forget that it is not 1988," said Secretary of State Condoleezza Rice. "It's 2008 and the United States has a ... firm treaty guarantee to defend Poland's territory as if it was the territory of the United States. So it's probably not wise to throw these threats around."

That treaty guarantee Rice referred to is, of course, the North Atlantic Treaty Organization, or NATO, Russia's old Cold War nemesis in Europe. The Soviet Union didn't survive the 1990s, but NATO did, and launched several rounds of expansions to bring into the alliance former Soviet satellites, including Poland. Russia has always viewed NATO expansion as a direct continuation of a Cold-War threat. Add treaty-destroying missile defenses to that expansion and it's not hard to see why Moscow was upset with the Bush Administration's plans, and prepared to fight dirty to protect its interests.

It was with this mutual nuclear bullying that U.S.-Russian relations perhaps dipped to their lowest. For just a couple months later, Barack Obama won the U.S. presidential election and, upon taking office in January, promptly extended Russia an olive branch.

"The last few years have seen a dangerous drift in relations between Russia and our [NATO] alliance," said Vice President Joe Biden. "It's time to press the reset button and to revisit the many areas where we can and should work together."

For starters, Obama would ask NATO to slow down its planned expansion into Georgia and Ukraine.

Second, Biden said America would continue to develop missile defenses, but less aggressively and in "consultation" with Russia. Ironically, then-President Vladimir Putin had proposed that very thing during a conference with then-President George W. Bush in 2007. Putin had even offered to host portions of the missile defense system on Russian soil. "We would be prepared to engage in this system also a newly built radar, early warning system, in the south of Russia," Putin said. "That cooperation, I believe, would result in raising to an entirely new level the quality of cooperation between Russia and the United States."

Bush didn't take him up on the offer, but Obama just might.

The thaw in U.S.-Russian relations quickly bore fruit elsewhere in the two nation's military operations. Russia volunteered several warships to assist a U.S.-led international naval force patrolling East African waters to deter Somali pirates. In February, a lightly armed U.S. Navy ship called for Russian help after it spotted suspicious boat that the American crew thought might belong to pirates. A Russian helicopter rotored in from a nearby warship to check out the boat.

The Russian lifeline

The most dramatic sign of U.S.-Russia rapprochement played out in Central Asia.

In recent years, Taliban fighters have begun targeting the eastern supply lines supporting U.S. and NATO troops in Afghanistan. Fighters have burned hundreds of supply trucks at depots in Pakistan, and destroyed key bridges spanning treacherous mountain passes.

Damage to the supply routes through Pakistan forced the U.S. to relay more heavily on its northern routes. The Pentagon maintains a major logistical hub at Manas air base in Kyrgyzstan. But the former Soviet Republic was always a reluctant ally, and in early 2009, the Central Asian nation's parliament voted to kick America out of Manas. U.S. military forces have until March to depart.

"I would say that Manas is important, but not irreplaceable," Gates said. Indeed, in February the U.S. inked a deal for another northerly route into Afghanistan ... through Russia and, presumably, one of its other former republics that abuts Afghanistan. Moscow insisted at first that only "non-lethal" cargo could pass through -- no ammunition -- but later flexed on that point too. "Other agreements are also possible," Foreign Minister Sergey Lavrov said.

With the signing of the supply arrangement, the U.S. and Russia -- indeed, NATO, as well -- have become strategic partners in the Afghanistan war. Few expected such a development. After all, Russia has objected to NATO's ongoing expansion and its recent military adventurism, viewing the alliance as a growing threat to Russia's hegemony. Georgia's attempts to join NATO had been a big factor in the tensions leading up to 2008 war with Russia. By helping supply the Afghanistan war, Russia is helping NATO wage its first shooting war.

The oil buzz wears off

How do we explain Russia's about-face? Are improved U.S.-Russian relations mostly the result of Obama's more inclusive philosophy, as they appear to be at first glance? Or are other factors at work? It's an important question, for it frames the way forward for both nations. Who really has the most power here?

The waxing and waning of the energy economy is one factor worth considering. Russia's combativeness in 2007 and 2008 was funded, to a great extent, by high oil prices. "Oil, natural gas ... left the former communist nation bristling with cash, pride and unprecedented global influence," concluded Knowledge@W. P. Carey, an Internet think-tank.

In less than a decade, Moscow saw the value of its publicly traded stocks soar from $74 billion to $1 trillion. But when oil prices collapsed in late 2008, sliding from a high of $150 per barrel to around $40, Russia's clout collapsed too. The Kremlin announced it would cut its military budget by 15 percent. The U.S. military said it would cut less than only a few billion from its own estimated $550-billion annual budget.

In the context of Russia's military cuts, the recent rapprochement with the U.S. can be read as a self-preservation strategy. Russia could no longer afford to stand toe-to-toe with America, so Moscow could either find common ground with the U.S. quickly, or suffer humiliation as the scale of its economic woes became clear.

But there's another way to read the new U.S.-Russian alliance. From a certain point of view, the partnership has hugely boosted Russian influence, and has done so despite the erosion of Russia's energy economy. "Obama is painted into [a] corner ... a Russian-Afghan one," Eric Walberg wrote for OpEdNews.com. "Is U.S. police now being made in Moscow?"

The answer to that question depends on which came first: Obama's peace offering or Russia's roads. If Obama decided to scrap missile-defense in Poland and put on hold NATO expansion because it needed Russian access to Afghanistan, then Russia indeed is exercising greater control over U.S. foreign policy, as an ally, than it did as a reborn Cold-War enemy.

But if Russia offered road access as a way of saying thanks, no hard feelings, after Obama had unilaterally abandoned missile defense and NATO expansion, then Russia is groveling and holds no real sway over American policy.

There's perhaps a hint to the truth behind the rapprochement. In the months before Kyrgyzstan's parliament voted to kick American out of Manas, Russia had offered the former Soviet Republic a generous economic aid package including $2 billion in loans and $150 million in grants. Appearances are that Russia bribed Kyrgyzstan into rejecting the U.S. military presence, thus positioning Russia to trade overland supply routes for concessions on NATO expansion and missile defense.

Regardless of who's got the upper hand -- Moscow or Washington -- there's reason for everyday people to be grateful for the way U.S.-Russian relations have panned out. A new Cold War was probably never truly likely. But neither Americans nor Russians benefited from the hostility that characterized the months prior to Obama's election. Whoever's really calling the shots, everyone is better off now that America and Russia are friends again.