to threat its ground force.

Think about it. US has surveillance orbital satellites, airborne surveillance airplanes, and long-range battle monitoring radars. As long as large clusters of tank columns are detected, what will happen? --- F-16, A-10, C-147, B-2, Apache-64 ..... all these attacking ground fighters and bombers will fly in like crazy bees and eliminate any enemy clustered armored ground force.

I guess the most effective way to attack US ground force is what Iraqi insurgents are doing --- roadside bomb or suicide bomb, a typical modern gorilla tactic.