I wonder if anyone realizes the irony that the only reason we are free to have this discussion anyway is largely because Americans were willing to fight, kill, and die in the service of freedom.
From an intellectual, theoretical point of view, war is a terrible thing that should be avoided if possible. In an ideal world, war would never be necessary.
But here, on planet Earth, in reality, there are bad people out there. And life is, unfortunately, not fair.
Who is giving the US the right to replace the regime in Iraq? How about the same people that gave the US the right to replace the regime in France in 1944. The American people. (Vichy France was technically a sovereign country whose government was overthrown by the US and a "friendly" regime - i.e. De Gaulle, installed).
But let's no kid ourselves, it's not wishful thinking and warm fuzzy thoughts that brought us the freedom we all enjoy today. It wasn't love that made the Internet. It was predominately American military might (the Internet came from a cold war military project for instance).
That we live today in countries where individual freedom is respected wasn't inevitable. In many respects, it was a miracle. Two horrific genocidal powers nearly engulfed the world -- Nazi Germany and Soviet Russia. Take the US and its willingness to fight for other people's freedom away and the world would be a much worse place.
The Iraqi people deserve such freedom as well. No, that's not the reason why the US is going to end up liberating Iraq anymore than liberating the Germans and French was the reason the US fought World War II. But that will be the end result.
In World War II, the easy path would have been to accomodate Hitler. But the UK and USA, alone of the major world powers who could have stayed out of the European conflict, chose to stand up for what was right (with Canadian and Australian help too).