[Clive]

"The Romans, too, won all the ground battles"

I hate to undermine a valid argument, but the Roman legions did occasionally lose. The battle of the Teutoburg Forest comes immediately to mind.

[Americanexpat]

The Romans may not have won all the battles but their empire lasted more than a thousand years. Nothing lasts forever. I remember when the Soviet Union fell, it was a surprise because I thought they would have lasted a lot longer.

What American Empire are we talking about anyway? The one that has won wars but rebuilds the country and then leaves it after a short time? If we were a real Empire we would be totally occupying parts of Europe, Central America, Asia and the Middle East.

[JasonC]

One of many http://ancienthistory.about.com/od/defeats/tp/Romandefeats.htm

Not to mention the countless Roman battles that had to be lost by a Roman army, because both sides were Roman armies. For four hundred years, two or more Roman armies chased each other around the Med, disputing possession of the ancient world. By late in that process, the men in those armies were mostly Germans of one variety or another, only the standards were still Roman.