Forces loyal to Libyan leader Moammar Gadhafi began to approach the eastern rebel capital of Benghazi on March 19, with the BBC reporting that loyalist armor already is inside the city, though this may have been only a reconnaissance element. Soon after these reports, word of impending international military operations against Gadhafi's forces began to emerge, with French and Italian aircraft reportedly beginning to conduct combat air patrols. Though Gadhafi declared a unilateral cease-fire in response to the U.N. Security Council's (UNSC) authorization of the use of force against Libya on March 17, it is becoming apparent that this was simply a stalling tactic in an attempt to consolidate gains ahead of airstrikes. The military incentive for Gadhafi is to reach Benghazi before any airstrikes begin. If a "no-drive" zone between Ajdabiya and Benghazi were to come into effect, military vehicles and supply convoys would be vulnerable to any coalition aircraft orbiting overhead, making it far more difficult for Gadhafi to project force across the large open terrain that separates the two cities. Airpower can also make it difficult to move and resupply forces, so the heavier elements of Gadhafi's forces — tanks, tracked vehicles and artillery — already operating at the end of extended lines of supply, may quickly face logistical issues. However, while airpower can attempt to prevent forces from approaching the city, it cannot force the withdrawal of those forces from within the city without risking significant civilian casualties. (click here to enlarge image) Relevant political negotiations and military planning now taking place in Europe continue, and more time is needed to mass forces for the impending air campaign against Libya. Nevertheless, if the European-led effort is to stop Gadhafi from reaching Benghazi, it will have to begin soon, with what forces have so far been moved into place — though, given Libya's distance from mainland Europe and the presence of U.S. Marine Corps, Italian Harriers and cruise missile-armed warships off the coast, there already is a considerable amount of coalition airpower in place. As nightfall approaches, loyalist forces with little night-vision capability may slow operations, and any air campaign against them will likely begin under the cover of darkness, consistent with longstanding U.S. and NATO operational practice. Targets are prioritized, so available airpower will begin to work down the list with the suppression of enemy air defenses as well as command, control and communications likely to be at or near the top of the list, though SA-7 man-portable air-defense systems and anti-aircraft artillery will remain a persistent threat. Rules of engagement will be an important question. While Gadhafi's forces have been led by a vanguard of T-72 main battle tanks and supported by BM-21 rocket artillery, his infantry is often videotaped using civilian vehicles for transportation. While the intention will likely be to stop all traffic between Ajdabiya and Benghazi, whether coalition aircraft are willing to fire on civilian vehicles remains to be seen. If so, they risk considerable civilian casualties. If not, they may deny the use of tanks and artillery but risk not stopping Gadhafi's infantry. The use of airpower has been authorized, forces are being massed, and Gadhafi appears to be acting as though its use is inevitable and so is moving while he can. However, the application of airpower entails civilian casualties, and it remains unclear if that application can be translated into the achievement of political objectives in Libya. So while there are many tactical questions moving forward, there is only one strategic one: How has the European-led coalition translated the UNSC authorization into military objectives, and what are the operational parameters and rules of engagement that govern them?