Land forces consist of combat units and support units. Ever since the Germans pioneered in the use of blitzkrieg (lightning war) tactics in 1939, properly-trained and equipped motorized armies have, under ideal conditions, been to advance very rapidly, up to 20 or 30 miles per day. With helicopter-borne airmobile units, even higher speeds can be achieved. The land forces of nearly all countries are organized in roughly the same hierarchical fashion. The basic unit is the division, with an average manpower of about 12,000; U.S. and NATO countries' divisions typically have more. The basic types of combat units are:
In addition to combat units, all major military formations have support personnel in such branches as logistics, medical, transportation, communication, etc. Without adequate, trained support it is impossible to sustain an offensive for any length of time because of the law of entropy: military units under fire tend to scatter and even fall apart unless they receive constant attention and replenishment. Most Third World military forces lack good support services, which detracts from the seemingly awesome force some of them (such as Iraq) possess. It requires at least a month for a country to mobilize its forces to prepare for war, and often several months to bring all of its reserve units up to combat readiness. Sustaining an offensive with modern high-technology equipment is prohibitively expensive for poor countries.
Naval forces The primary mission of naval forces is to protect a country's maritime commerce. Landlocked countries such as Austria and Bolivia have only token navies that patrol lakes and rivers. Modern navies consist of the following types of combat vessels:
Air forces are essential for maintaining effective control of a country's territory in the modern world, since unopposed enemy aircraft could quickly wreck the essential infrastructure of modern life: electric power grids, petroleum refineries, and bridges. Air forces are also critical for supporting land offensives and for protecting naval forces against enemy attack. There are three main types of combat aircraft:
In addition, some countries possess ballistic missiles, some of which can be launched against targets as far as 7,000 miles away; these long-range strategic weapons are called intercontinental ballistic missiles (ICBMs). It takes only about 30 or 40 minutes for such a missile to reach its target, so there is virtually no warning, even with the best radar systems. Anti-ballistic missiles were developed by the U.S. and U.S.S.R. to defend against missile attacks, but they are severely constrained under the terms of the 1972 ABM treaty. Fear of proliferation of missiles to "rogue" states such as Iraq and North Korea has led to new calls for the United States to build an limited-scale ABM system.
|1995 Rank (# troops)||Country||Military expenditures
(billion U.S. $)
|Number of troops
(as of 1995)
|Tanks||Combat aircraft||Nuclear warheads||Submarines||Aircraft carriers*||Cruisers||Destroyers||Frigates|
|2||United States||597.5||1,381||14||2,384||1,143||7,000||71||11 + 9||22||62||4 +|
|6||South Korea||33.5||633 *||26||2,418||488||0||23||0||3||6||14|
|25||United Kingdom **||55.1||192.7||3||227||148||215||16||2||0||6||13|
SOURCE: World Almanac and Book of Facts: 2017, based on International Institute for Strategic Studies, The Military Balance (annual book). "Divisions" are the equivalent number of standard-size units, about 12,000-15,000 personnel each; those data (for 1995) are from The Military Balance.
NOTE: Many of the above figures are estimates, and the reliability varies from country to country; military expenditures comparisons are very difficult. "Number of troops" include only active duty personnel.
* Countries whose reserve forces exceed regular active duty forces: Russia = 2,000,000; South Korea = 4,500,000; Vietnam = 4,500,000; Brazil = 1,340,000; Taiwan = 1,657,000; Israel = 465,000; Sweden and Switzerland also.
** Data on United Kingdom and Italy are for 2020; source: www.globalfirepower.com.
@ Under the 1994 Budapest Memorandum on Security Assurances, Ukraine transfered to Russia the nuclear weapons it had "inherited" from from the former Soviet Union, as did Belarus and Kazakhstan.
The U.S. Navy has 11 full-size aircraft carriers that carry 60-72 aircraft, as well as 9 amphibious assault ships that carry 6 "Harrier" VSTOL aircraft plus helicopters. The latter are closer to the size of aircraft carriers in most other countries. Since 2016, the U.S. Navy has phased out its inventory of frigates, and has introduced a new class of "littoral combat ships."