President Barack Obama laughed off Mitt Romney's argument that he had weakened the military through downsizing by joking that it was only natural for advancements in technology to make obsolete older weapons—such as those from the Civil War.

In a discussion about the size of the military, Romney went after the president for allowing the number of ships and planes to drop under his watch. Yet Obama struck right back, pointing out that older armaments will of course gradually be phased out when more effective alternatives arise.

"You mention the Navy, for example, and the fact that we have fewer ships than we did in 1916," Obama said. "Well governor, we also have fewer horses and bayonets."

"We have these things called aircraft carriers, where planes land on them," he added.

From there, Obama continued on the offensive, painting Romney as way out of his league on foreign policy and ignorant of the way the military is run.

"This is not a game of battleship," Obama said.

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