A little bit thin. Aside from Mexico and Canada all other US borders are naval. US marines were basically the same thing as were the Soviet paratroopers. You don't defend homeland with marines, you know. They had carriers so they could transport their armies (and airfields) overseas.
USSR had the land border with NATO and its tanks, according to the doctrine I've seen were to reach the Atlantic in 48 hours should the war start. This was necessary to neutralize the medium and short range missiles deployed in Europe. And, according to the stats I've seen, US almost all the time had more missiles and warheads than USSR (though it didn't really matter since it was 4x overkill). And USSR was ever the second in the arms race (if you count warheads only).