A strategic bomber is a heavy type aircraft designed to drop large amounts of ordnance onto a distant target for the purposes of debilitating an enemy's capacity to wage war. Unlike tactical bombers, which are used in the battle zone to attack troops and military equipment, strategic bombers are built to fly into an enemy's heartland to destroy strategic targets e.g. major military installations, factories and cities. In addition to strategic bombing, strategic bombers can be used for tactical missions.
At the start of the Second World War, most strategic bombing was carried out by medium bombers, typically twin-engined with several gun positions. Bigger two and four-engined designs were being developed and these came to replace the medium bomber designs.
More recent strategic bombers like the Rockwell International (now Boeing) B-1B Lancer bomber, Tupolev Tu-160 Blackjack and the Northrop Grumman B-2 Spirit bomber incorporate stealth features in their design in an effort to avoid detection. Non-stealthy strategic bombers, e.g., the venerable Boeing B-52 Stratofortress or the equally venerable Tupolev Tu-95 are still relevant through the use of air-launched cruise missiles and other "stand-off" weapons like JSOW and JDAM. Indeed, it is likely that the USAF B-52 fleet will, with continuing upgrades, outlive the B-1B fleet. However, the USAF has recently launched a program for a new strategic bomber to complement the current fleet; it is likely that this bomber will also serve as a replacement for both the B-52 and B-1. In the case of the Russian VVS (Air Forces), new Tu-160 strategic bombers are expected to be delivered on a regular basis over the course of the next 10-20 years. Additionally, the current Tu-95, Tu-142, Tu-26 and Tu-160 fleet will be periodically updated, as it was seen in the 1990s with the Tu-22M fleet.
During the Cold War, strategic bombers were almost certainly armed with nuclear weapons. However, since the end of the Cold War, strategic bombers have exclusively been deployed using non-nuclear, conventional weapons. During Operation Desert Storm, the invasion of Afghanistan, and the 2003 invasion of Iraq, American B-52s and B-1s were employed in both strategic and tactical roles. During the 1979-1988 Soviet-Afghan war, many Tu-95 carried out several mass bombings on several regions of the country.