>now our southern border could be invaded by full blown warships. We have 12,383 miles of oceanfront coastline as it is. What's another 2000 miles or so? Yeah, the guy's proposal (2 miles) is ridiculous. It could be wide enough to support bidirectional supertankers and cargo ships, maybe 4 lanes. It would dwarf the Panama canal. I like the idea but think the cost would be ridiculous, wraught with technical challenges.