"I believe America is safest and strongest when we are leading the world and we are leading strong alliances. I'll never give a veto to any country over our security. But I also know how to lead those alliances. This president has left them in shatters across the globe, and we're now 90 percent of the casualties in Iraq and 90 percent of the costs." Read it how you want.
He used some sloppy language but what he clearly meant was military casualties and that we are shouldering almost all of the military casualties which is correct.