Destroyers to the rescue?

According to the TV newsie, the US is massing destroyers off the coast of Syria to do a little 21sth century gunboat dipomacy. 
Destroyers?  The smallest warship that counts as a ship?  Smaller vessels are known as boats, not ships.  Either 21st century destroyers are a LOT bigger and meaner than 20th century destroyers, or the proposed strike on Syria is gonna be a lovepat.  I mean, we used to do this sort of thing with aircraft carriers, no destroyers need apply. 
    Actually, destroyers have gotten bigger and costlier over the years.  Used to be, a destroyer was only 2000 tons displacement.  Lately they have been pushing 5000-6000 tons.  Ships that big used to be called cruisers.  Now they are destroyers.