If the US had to assault a beach today, the assault would have to be conducted from over the horizon in order to avoid being targets for anti-ship missiles launched from several miles inland. This would push amphibious ships back approximately 15-20 nautical miles, stretching the range of current AAV range, which would work in conjunction with assault aircraft and helo's. Factors to consider are sea state, enemy defenses, maneuverability of nearby enemy armies, range of landing craft, potential casualty rate, availability of logistical support upon landing etc. All of these factors come into play when launching an amphibious assault, and each and every factor has an acceptable "failure rate", which may or may not become a limiting factor with respect to launching the assault.
These 7 photos show how the Marines assault a beach
0100: Begin aerial and missile bombardment
0200: Launch amphibious landing craft (AAV's)
0415: Launch helo assault and gunships e.g., V22 Ospreys, Super Stallions and Cobra's.
0455: AAV arrival at surf zone outside of target objective, halt missile and aerial bombardment.
0500: AAV' assault beach and begin suppressing fire on target where necessary with accompanying infantry.
0505: V22 and Super Stallions drop reinforcing infantry battalion.
0600: Beach secure, begin landing heavy armor and logistical support.