When we think of a nuclear weapon, we picture a city wiped out — in the plural, the entire world. But nuclear weapons come in different shapes and sizes. The larger versions are called “strategic,” apparently because the overarching strategy of a war is fashioned around their use. Those smaller in yield are called “tactical.” That is, using them is a tactic in a war smaller than all-out nuclear. Also, while both can be delivered by bombers, strategic are delivered, as well, by long-range intercontinental ballistic missiles while tactical are confined to short-range missiles or bombers.

The nuclear bombs dropped on Hiroshima and Nagasaki, though of a yield that would count them as tactical today, were considered strategic because they were intended to wipe out entire cities, which tactical aren’t. Nor have tactical, to the best of our knowledge, been used. But they constitute as much of a nuclear threat as strategic.

Tactical weapons tend to blur the distinctions between nuclear and conventional weapons, thus acting — overused-term alert! — as a gateway drug to strategic nukes.. In addition, they’re expensive, and they’re a sticking point between the United States and Europe, and between the United States and Russia.

Regarding the expense, in a Foreign Policy piece titled A Steal at $10 Billion, Jeffrey Lewis of the James Martin Center for Nonproliferation Studies writes about the aircraft-delivered tactical weapon the B-61.

There is now a furious debate about whether the United States needs to modernize the B61, which dates to Lyndon B. Johnson’s administration, making it the oldest design left in the stockpile. Sen. Dianne Feinstein (D-Calif.), chair of the Senate Appropriations Subcommittee on Energy and Water Development, recently revealed that the cost of the program to extend the bomb’s life has more than doubled: Modernizing the approximately 400 B61 gravity bombs in the stockpile will cost $10 billion. That is billions with a “B.”

Regarding the divisiveness they incur between the United State and Europe, he writes:

Look, America’s European allies don’t value U.S. tactical nuclear weapons. Yes, some of them, especially in a few defense ministries, say they do, but actions speak louder than words. The United States’ NATO allies value nuclear weapons so much that they aren’t willing to properly fund the mission. [On their security] No matter what some European officials say, the actions of European hosts say they don’t care.

As for abolishing them, in May of this year Amy F. Woolf of the Congressional Research Service wrote:

In contrast with the longer-range “strategic” nuclear weapons, these weapons had a lower profile in policy debates and arms control negotiations, possibly because they did not pose a direct threat to the continental United States. … In 1991, both the United States and Soviet Union announced that they would withdraw from deployment most and eliminate from their arsenals many of their nonstrategic nuclear weapons.

The United States now has approximately 1,100 nonstrategic nuclear weapons … but experts believe Russia still has between 2,000 and 6,000 warheads for nonstrategic nuclear weapons in its arsenal. … Many analysts argue that the United States and Russia should, at a minimum, provide each other with information about their numbers of nonstrategic nuclear weapons and the status. … Russia, in particular, has seemed unwilling to provide even basic information about its stockpile of nonstrategic nuclear weapons. Some in the United States have resisted as well, arguing, in particular, that public discussions about the numbers and locations of U.S. nuclear weapons in Europe could increase pressure on the United States to withdraw these weapons.

Worse, other states, such as Pakistan, have developed tactical nukes, too. Also at Foreign Policy, in a piece titled Race to the End Tom Hundley writes:

This April, Pakistan tested a short-range ballistic missile, the Hatf IX, a so-called “shoot and scoot” battlefield nuclear weapon aimed at deterring an invasion by India’s conventional forces. This development carries two disturbing implications. First, Pakistan now has the know-how to build nuclear warheads compact enough to fit on the tip of a small missile or inside a suitcase (handy for terrorists). Second, Pakistan has adopted a war-fighting doctrine that does not preclude nuking its own territory in the event of an Indian incursion — a dubious first in the annals of deterrence theory.