As the Ukraine-Russia crisis deepened and West-Russia relations plunged to their lowest point since the Cold War, Moscow has rattled its nuclear saber. Russian strategic rocket forces have conducted an increased number of exercises, Bear bombers have probed the air defenses of NATO members, and Vladimir Putin has engaged in nuclear chest-thumping.

All this aims at getting attention, and it has done so. Analysts have sounded the alarm in Washington as Russia upgrades or develops plans to upgrade all legs of its strategic triad.

The Pentagon must closely track trends in Russian strategic nuclear forces. Russia is America’s only peer competitor when it comes to nuclear weapons. The size and structure of Russian strategic nuclear forces will affect decisions regarding the size and structure of U.S. strategic nuclear forces.

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One should, however, keep Russian strategic force developments in perspective. That means taking a number of factors into account: the overall strategic balance, the fact that Russian modernization is taking place after a lengthy pause, the difference between Russian and U.S. strategic modernization cycles, and the longer service lives of U.S. strategic weapons systems.

Consider first the balance of U.S. and Russian strategic nuclear forces. The 2010 New Strategic Arms Reduction Treaty (New START) requires that, by February 2018, the United States and Russia each reduce its strategic forces to no more than 700 deployed intercontinental ballistic missiles (ICBMs), submarine-launched ballistic missiles (SLBMs) and strategic bombers and no more than 1,550 deployed strategic warheads.

According to data exchanged under New START, as of October 1, 2014 the United States had 1,642 deployed strategic warheads, compared to 1,643 for Russia. The number of deployed ICBMs, SLBMs and strategic bombers for the United States was 794, compared to 528 for Russia. There exists a balance in deployed strategic warheads, with the U.S. military holding a substantial numerical advantage in the number of deployed strategic delivery vehicles. That advantage will persist for many years.

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These numbers conceal an additional area of U.S. advantage. The U.S. military has “downloaded” all of its ICBMs and most, if not all, of its SLBMs. As a result, the missiles carry fewer warheads than their maximum loadings.

The Trident D-5 SLBM can carry eight warheads. Under New START, the Trident D-5s carry an average of only four to five warheads. All Minuteman III ICBMs have been downloaded to carry a single warhead, even though two-thirds of them could carry three.

The U.S. military also maintains a large number of non-deployed nuclear warheads in storage. If New START were to break down, the United States could add hundreds of nuclear warheads—well over 1,000—to its strategic ballistic missile force. The Russian strategic ballistic missile force has nowhere near the capacity to match that.

Russia has an array of strategic modernization programs underway. It has launched the first three of what are planned to be eight Borey-class ballistic missile submarines, which carry the new Bulava SLBM. Russia is also deploying the SS-27 Topol-M ICBM and its multiple-warhead variant, the RS-24 Yars, and plans to begin deployment of the RS-26 ICBM in 2016. The Russian Air Force is developing a new strategic bomber, the PAK-DA, to augment or replace its Tu-160 Blackjack and Tu-95 Bear-H aircraft.

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Russia’s strategic modernization programs and strategic activities are indeed far more robust today than they were ten or fifteen years ago. But much of that is playing catch up. Following the collapse of the Soviet Union in 1991, the Russian economy went into freefall. Defense spending crashed, and the Russian military bought little in the way of new strategic weapons in the 1990s and early 2000s. Many missiles, such as the SS-18 and SS-19 ICBMs—which today still carry about one-half of Russia’s deployed strategic warheads—have reached and passed their service warranty dates.

The combination of retiring old systems and deploying a limited number of replacements brought the level of Russian strategic forces steadily down from 1991 until 2010. Russian strategic delivery vehicle and accountable warhead numbers fell well below the limits established in the 1991 START I Treaty (which expired in late 2009).

Rising oil prices in the early-mid 2000s boosted the Russian government’s revenues and prompted a rebound in defense spending. Increased funding led to the new missiles and submarines that are coming online now. Growing revenues also allowed Moscow to restart activities that had been on a long hiatus, such as a resumption of global flights by Russian long-range bombers.

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A second consideration is that the United States and Russia are on different cycles when it comes to strategic force modernization. We have seen this before. The Soviet Union deployed significant numbers of (then) new strategic systems in the late 1970s and early 1980s. Those included the SS-18 and SS-19 heavy ICBMs and Blackjack bomber, as well as the Typhoon-class ballistic missile submarine (of “Hunt for Red October” fame), which was armed with the R-39 SLBM.

U.S. strategic modernization peaked some years later. The U.S. military deployed the new Ohio-class ballistic missile submarine, Trident D-5 SLBM, MX ICBM and B-1 and B-2 bombers in the 1980s and early 1990s.

Russia’s strategic modernization program today appears to far outpace U.S. efforts. Flash forward ten years, and the picture will look very different.

By the early 2020s, barring delays brought about by a slowing economy, the Russian military will have completed most of its strategic update programs, with the possible exception of a new bomber. In the mid-2020s, the U.S. military will be building new ballistic missile submarines to replace the Ohio-class boats, a new long-range strike bomber and perhaps a new nuclear-armed cruise missile. It will also be preparing either to build a new ICBM or to modernize and further extend the life of the Minuteman III ICBM, a less expensive option. The United States will then dominate on strategic modernization.

A third consideration is that the U.S. and Russian militaries have different philosophies when it comes to how they build, maintain and operate strategic offensive systems. Russia, like the Soviet Union before it, builds a strategic missile, generally keeps it in the arsenal for a shorter time than its American counterpart will spend, and then retires the missile and builds a new one.

The U.S. military tends to keep missiles in the force for considerably longer periods of time, using life extension programs to ensure their continued longevity as well as to modernize them. That is a Pentagon policy choice, which balances cost, reliability and effectiveness factors.

For example, the U.S. Air Force first deployed the Minuteman III ICBM in 1970. Under the New START Treaty, the Air Force intends to maintain 400 deployed Minuteman III missiles. The missile will remain operational until 2030, and one option for modernizing the ICBM force is simply to extend the life of the Minuteman III beyond 2030.

The Minuteman III’s Russian counterpart is the SS-25. First deployed in 1985, fifteen years after the Minuteman III, only about fifteen of these ICBMs remain in the Russian inventory. The remainder will be retired from service by 2020, if not earlier. Most SS-25s have served only about one-third as long as the Minuteman III will serve.

Consider the two countries’ respective SLBMs. Russia has begun to deploy the Bulava SLBM, which made its first flight test in 2005. The U.S. Navy’s SLBM is the Trident D-5, first flight-tested in 1987 and deployed in 1990.

Newer does not always equate to better. The Bulava missile has failed in roughly 40 percent of its 21 flight tests over the past ten years. The older Trident D-5, on the other hand, has a stunning record of more than 140 consecutive successful flight tests.

None of this is to suggest that the United States can ignore Russia’s ongoing program to modernize its strategic forces. Some elements are troublesome.

For example, the Russian military is developing the new Sarmat ICBM, which will reportedly be capable of carrying as many as ten-fifteen warheads. Too large to be mobile, the liquid-fueled Sarmat will be silo-based. Russian analysts have criticized the planned program as destabilizing, particularly in a crisis. They note that large, multiple-warhead ICBMs in silos present attractive targets for a preemptive strike. Indeed, the U.S. Air Force decision to download its Minuteman III ICBMs was driven in part by the calculation that a single-warhead ICBM in a silo would, in a crisis, offer a less inviting target.

Russia remains the only country that could physically destroy the United States, so Russian strategic forces matter. Washington needs to make wise investments in its own strategic forces. If it does, current Russian programs present no cause for undue alarm—particularly as Moscow continues to adhere to the limits of the New START Treaty.

And if there is a senior American military officer who would like to swap U.S. strategic nuclear forces for those of Russia, he (or she) has yet to speak out.

Steven Pifer directs the Brookings Arms Control and Non-Proliferation Initiative.