I've got a quick question. If my opponent normal summons a monster and I negate it with say Forced Back or Horn of Heaven, would he be able to get another normal summon since technically his Normal summon never took place. He's placing this akin to the ruling on cards like say Goblin Attack Force if it's attack is negated it remains in Attack mode. Quick responses are welcome.

( I already know, he's just being stubborn :P )

You can't summon again. That's it. You get one shot at a normal summon. If it's negated, you lost your privilige.

EDIT: In regards to the Goblin Attack Force, that requires the attack to go though. If the attack doesn't go through because it's negated, then it doesn't go into defense position. But it can't attack again either.

Just to back it up....

Even though something being "Negated" makes it seem like the card was never used (which is why Jinzo is affected and priority is halted), it does NOT change the fact in terms of the game that such an act has already been performed.

So an attack being negated does not change the fact that you declared an attack with the monster, so the monster cannot attack again unless it can attack multiple times.

Or if you Normal Summoned, you cannot Normal Summon again unless you got Ultimate Offering in play.

And so on and so forth.

Because, in essence, each monster can only attempt to attack once (unless it's something like Mataza) and each player can only have one attempt at a normal summon. That may sound a little more clear.