What's the difference between Mechanized Infantry and Armored Cavalry? Is there one? Is it a stupid question to begin with?
Primarily, the difference is organization and mission. A mechanized Infantry unit is infantry with its own, organic armored vehicles, (in these days, Bradleys), they are organized in companies, battalions, brigades, and divisions. In larger units, (brigades and above) they have tank, artillery, air defence, aviation, support, and scouting (which may be cavalry!) units attached to them. In smaller units, (battalion and below), they contribute the infantry weapons such as the Javelin ATGM, the Stinger, their rifles and machine guns, as well as the firepoer of their Bradleys, to a "task force" that will also have these other combat elements assigned to them. They fight the main offense or defense, or provide security in an area by manning checkpoints, etc. Cavaly are organized in troup (equivalent to company), regiment, brigade, division. A "regiment", unlike an infantry battalion, has its own artillery and other units organic to itself - so it is more capable of independant action. Consequently, cavaly units tend to fill different missions - they are more likely to be used for scouting, delay, economy of force, mobile reserve (cavalry riding tot he rescue....etc.), reaction force, etc. While in theory, either could do the other's mission, a cavalry unit is better prepared by training, organization, and doctrine for the types of missions I've listed for them, whereas the Infantry fights as part of the larger offense or defense. Hope this helps - others correct me where I may have errred.