Russia's explicit threat issued Wednesday to shoot down missiles and target deployment sites in the event of a U.S.-led military strike on Syria has caused a great deal of consternation. The statement fits with a Russian pattern of threats against U.S. assets in the war-torn country, and it is not likely to change U.S. intentions to punish the Syrian government for its purported use of chemical weapons against a rebel-held area. The latest developments appear to be just another chapter in the continuing back and forth between the countries over Syria....