The idea that if we had "concentrated" on Afghanistan, that the war there would have been more successful, has no real basis in fact. For one thing, the war in Afghanistan began almost a year and a half before the invasion of Iraq.

The "more troops" myth: As with Iraq, nobody has been able to really specify exactly what more troops would have actually done on the ground, given the rules of engagement (which are a whole separate argument by themselves.)

One example: twice as many Americans standing around while the Afghans screwed up the attack on Tora Bora would have accomplished...what?

Just like in Iraq. If you aren't allowed to shoot looters, overrun cities full of insurgents, attack mosques full of rebels, or do any of the other "killing people and breaking things" that the military is designed for, what good does it do you to have more troops on the ground? A convoy twice as long just means more trucks to hit roadside bombs. More divisions means more targets.

You might make a case that you could tighten the borders with more troops, but we aren't allowed to stop civilians (at least they look like civilians) from streaming into Iraq from Iran on pilgrimages, are we?

I hate to point out to you that Iran is working with the bad guys. They weren't going to "seal their borders" just because we stayed out of Iraq after taking over Afghanistan.

To the best of my knowledge, every NATO nation is currently participating in Afghanistan, including France. Maybe they would have more there if we weren't in Iraq. Maybe not.

Saddam is really "contained" now. Not just hopefully.