Russia's relations with the West have run off the rails and into a deep ditch -- invective and stones flying. But does the wreckage deserve to be described as a new Cold War?

Many who say -- or at least hope -- the answer is no insist that the current crisis over Ukraine has too few similarities with the original.

Too short when compared with 50 years of enmity. Too much a U.S.-Russia feud rather than a conflict engulfing the whole global system.

Too little hostility, and lacking a deep ideological divide. And, this time, happily without the constant dark shadow of nuclear Armageddon.

But to take comfort in these valid contrasts risks obscuring the unhappy qualities the two episodes share, and, more seriously, underestimates the scale of the damage done and the pain yet to come.

Placing all the blame on the other side for the collapse, and ignoring the toll taken by the mistakes and myopia of both, mirrors the early phases of the first Cold War.

Assuming that the core of the problem lies not only in the other side's behavior, but in the nature and character of its leadership and politics, is also pure Cold War.

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So too is cutting off ties, refusing to engage, reaching for sticks and forgetting the carrots, and writing into law barriers to future cooperation.

The eagerness to see the threat in narrow national security terms, requiring a renewed call to arms and alliances, and a tendency to focus on tactical goals rather than the longer term future of U.S.-Russian relations, reinforces the comparison.

If today's crisis is judged in the context of the 25 years since the fall of the Berlin Wall, each side is guilty, and recognizing that is more important for the future than deciding who is most to blame.

That future could be much bleaker than the vast majority of American politicians, media, and public have yet grasped. Their Russian counterparts are no wiser.

Events in Ukraine pose an indisputable menace that has to occupy U.S. leaders. But the response must consider what a deepening and prolonged Cold War II would mean.

Fancy concepts are not needed to convey the costs. What, if not a bilateral Cold War, has marked U.S.-Iranian relations since the 1979 revolution? Translate the nature of that relationship over the last quarter century into a U.S.-Russian relationship that looks very similar for the next 25 years.

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Both sides are already marching in that direction, giving up on the useful ambiguity of regarding the other as neither quite friend nor foe. Instead each now views the other as an adversary bent on thwarting and, where possible, damaging its interests.

As a result, when US.-Russian leadership is needed more than ever to cope with the instability of nuclear proliferation and the militarization of space, they are allowing the arms control regime painfully constructed over the last 40 years to die a slow death.

As adversaries, they're unlikely to work well together to counter cyber warfare, climate change and catastrophic terrorism. The temptation will be to use these, and other titanic changes such as China's rise, against each other. Rather than sponsoring enhanced European security, they are leading the charge in re-militarizing Europe's core.

The eight U.S. presidents and six Soviet general secretaries who presided over the original Cold War eventually engaged one another in taming a nuclear arms race, cooperating in space and linking energy resources -- before Mikhail Gorbachev and Ronald Reagan called the whole thing off.

But they only did so after fighting the Korean, Vietnam, and Afghan wars, risking nuclear war in Berlin twice, the Cuban missile crisis, and the 1973 Yom Kippur War. Between them they spent as much as $20 trillion on arms and accumulated 70,000 nuclear weapons.

One hopes that their successors will not take so long, run so many risks, and pay so high a price before repairing a relationship that is vital to tackling this millennium's urgent challenges.

Robert Legvold is Marshall D. Shulman Professor Emeritus of Political Science at Columbia University and the author of Russian Foreign Policy in the 21st Century and the Shadow of the Past. The opinions expressed in this commentary are solely those of the author.