Don't expect too much.
[L]imited wars tend to have far more limited results and uncertain consequences than their planners realize at the time they initiate and conduct them. . . . learn what cannot be done . . . avoid setting goals [for intelligence and technology] that are impossible, or simply too costly and uncertain to deploy. . . . pursue a decisive strategy within the limits of the war. . . . prepare for conflict escalation, alternative outcomes and "plan B" . . . prepare for conflict termination. . . . the advocates of airpower tend to sharply exaggerate its ability to influence or intimidate leaders and politicians, and act as weapons of political warfare. . . . such attacks provoke more hostility and counterescalation.
Don't kill innocent bystanders without a damn good reason.
The key issue for the U.S. are what can be done to . . . reduce civilian casualties and collateral damage. . . . The U.S. needs to approach these problems with ruthless realism at the political, tactical and technical level. It needs to change its whole set of priorities affecting tactics, technology, targeting and battle damage to give avoiding unnecessary civilian casualties the same priority as directly destroying the enemy. This means working with local allies and using HUMINT to reduce damage and political impacts. It also means developing real time capabilities to measure and communicate what damage has actually been done. . . . It must develop clear plans and doctrines regarding proportionality and be just as ready to explain and justify them as it is to show how it is acting to limit civilian casulties and collateral damage. Above all it must not fall into the trap of trying either to avoid the laws of war or of being so bound by a strict interpretation that it cannot fight.
Understand your enemies and potential allies.
Modern nations must learn to fight regional, cultural and global battles to shape the political, perceptual, ideological and media dimensions of war within the terms that other nations and cultures can understand, or they risk losing every advantage that their military victories gain.
Non-state actors can employ high technology weapons and low tech stealth.
A non-state actor can have great military capabilities "when it achieves advanced arms, and it has strong outside support from state actors." These include medium and long range missiles (although destroying these weapons was one of Israel's main successes in the war), anti-ship missiles, high tech anti-tank weapons, and man portable surface to air missiles.
Technological surprise "is almost unavoidable when deliveries are high and many weapons are small and/or are delivered in trucks or containers and never seen used in practice."
[All] systems that are not vehicle mounted are low signature weapons that [are] very difficult to characterize and target and easy to bury or conceal in civilian facilities. Stealth is normally thought of as high technology. It is not. Conventional forces still have sensors geared largely to major military platforms and operating in environments when any possible target becomes a real target.
Beware proxy forces.
Playing the spoiler role in arming non-state actors even with relatively advanced weapons is cheap by comparison with other military options. The U.S. must be prepared for a sharp increase in such efforts as its enemies realize just how cheap and easy this option can be.
Prepare for asymmetric warfare.
[There are] potential areas of vulnerability in U.S. forces and tactics non-state or asymmetric actors can exploit [which the] U.S. must anticipate and pre-empt when it can, and share countermeasure tactics and technologies with its allies.
Train for the next war.
Military forces must prepare for the wars they may have to fight, not for the wars they want to fight. They must also prepare knowning that nothing about the history of warfare indicates that peacetime planners can count on predicting when a war takes place or how it will unfold.
Missile defense has limitations.
There is nothing wrong with active missile defenses, provided they can be made cost-effective. This war, however, is another warning that they will never by themselves be an effective method of defense against the full spectrum of possible threats.