Although the U.S. Army dropped bayonet training three years ago, most ground troops world-wide still get some of it. Some army personnel want to bring it back. The U.S. Marine Corps still trains riflemen on how to use the bayonet, as does Britain. In fact, British troops were the last troops to actually use a bayonet charge in combat. This happened in 2004, when a patrol of 20 British troops in Basra, Iraq were ambushed by about a hundred Iraqi Shia militiamen. Help was still on the way when the commander of the British troops realized they were running out of ammo and the Iraqi gunmen were moving closer. So he ordered his troops to fix bayonets and charge. That thoroughly demoralized the Iraqis who, after some close combat with the British (Scots, actually) left 35 of them dead, all ran away. Some of the British troops were wounded but all survived. This, however, was one of the very few such incidents of bayonet use in the last decade. The problem is that Western troops tend to be well trained marksmen and Iraq or Afghan gunmen have learned not to get too close. So opportunities for launching a bayonet charge are increasingly rare.
While the U.S. Army eliminated bayonet drills from basic training, the U.S. Marine Corps has not. The marines did this not so much for developing weapons skills but for mentally conditioning marines for combat. The bayonet drills are part of larger program emphasizing one-on-one combat. The army does this, to a lesser extent, and now without bayonet training.
The army attitude towards close combat is a bit different and always has been. While the bayonet and the bayonet charge have a firm place in military history, the reality is rather different. This has had a heavy influence on the army bayonet training decision. Bayonets are often still carried but rarely attached to the front of a rifle. Most modern bayonets are simply knives, which are handy for all sorts of things on the battlefield. Sticking them in the enemy is rarely one of them. Army leaders saw training new recruits in the battlefield use of the bayonet as misleading and a waste of time. The marines looked beyond the weapon, to the spirit and enthusiasm with which it, and many other implements of destruction, are used in close combat.
The marines recognized that while the "bayonet charge" may not happen on the battlefield much anymore, it is still part of the American memory and perpetuated via all sorts of media. The marines use that sort of thing to get their recruits in shape for the battlefield. The marines have always been pretty good at that. Recruits are led to believe that the bayonet practice is some kind of game, and competition, but one with a deadly serious purpose.
But why do infantry continue to carry a bayonet? To a certain extent carrying a bayonet is tradition, even in the army. But there are practical reasons as well. A lot of time is spent out in the field and a knife is useful for cutting stuff. But perhaps the most effective military use is intimidation during efforts to calm down rioting civilians. This is nothing new, the fearsome effect of a bunch of guys advancing with bayonets on the end of their rifles has been known for centuries. It's also a morale boost for the lads using the bayonets. When you hear the order "fix bayonets" (put them on the end of your rifle) you feel that it is do-or-die time, even if it isn’t. Unfortunately that order is rarely given anymore. In the army the troops prefer to carry a hunting knife or multitool and most units never let the bayonets leave the arms room.
The most common "combat" use of bayonets is for crowd control. In fact, this is about the only "bayonet training" most troops get anymore. The bayonet is used somewhat differently in these situations. For one thing, the troops don't just rush at the crowd carrying their bayonet tipped rifles. They march forward, neatly lined up, with the rifles held so that the crowd sees a line of bayonets coming at them. The troops do this while marching in step and are trained to bring their right feet down as heavily as possible. The sight of the advancing troops, the bayonets, and the rhythmic thud of boots striking the ground usually causes the crowd to scatter.
The marines train their recruits to understand that they might have to "fix bayonets" in combat and that they must know how to fight with a bayonet and anything else they can get their hands on or just with their bare hands. Thus, in type of bayonet training, it's the thought that counts.