At Algiers the resistance had indeed taken out much of the opposing artillery. They only really came into play hours after landing. At Oran and Casablanca, they were not so lucky. However, none of those were actually port landings. There were multiple landings on the flanks of the cities. The Cities were taken from overland. The allies (Not just US) did send men directly into harbour to try and keep the harbour facilities from being destroyed but in both cases it ended with most of the attacking force killed or captured and the ships used to get them there mostly sunk. Its not a ringing endorsement of Port to Port attacks.Not clear what guns it was against, but pretty sure the USA put troops ashore, 'port to port' at Algiers during the Torch operation in 1942. Unless local resistance members had knocked out any and all harbour defences or something, the USA showed it could be done - and done successfully - during WW2.