Actually the only time the marines go in it is when we are invading from sea, like normandy. but if we are going from land the army is first. the army has a much larger mechanized force (tanks and armor vehicles) than the marines.
Not to mention the battle fields of history are lined with young kids filled with propagandic notions of glory and freedom. The US is not free it hasn't been since the turn of the century, the US is one of the most oppressing nations in the world. Our country has over 5 million people locked up, and most of them are from nonviolent bullshyt drug charges or from the inability to pay the fines or taxes our corrupt government instills on it's citizens. I and everyone else is forced to give up 1/3 of our money or we will be jailed. And this is freedom? Extortion?