The US has on thousand times the population it had when the outsiders came when the natural balance was fairly neutral. Those 1,000X citizens have resource appetites of thousands of times the original inhabitants.

The natural balance is so horribly out of balance it can likely not be restored short of major adjustments in consumption habits. Whatever we drive, we are going to have to drastically alter our notion of how much mileage is acceptable if the planet is going to survive. We have already done immeasurable irreparable harm. All we can do now is to limit our future harm.

SUVs do more harm than "normal" cars, but *all* cars represent a huge consumption of resources, vaster than our predecessors and more than the Earth can handle. Rationalize it however you want to. That will not alter this reality.