The law of averages predicts that at some time in the future, perhaps as soon as 2017, the Democratic Party will once again control the White House and majorities in both houses of Congress. When that happens, the next Democratic president -- be it Hillary Clinton or someone else -- will sign into law a sweeping, foreign-style gun ban. The legislation has already been written. H.R. 4269 would enact a national, permanent ban on the manufacture and sale of so-called “assault weapons” and all firearm magazines capable of holding more than 10 rounds. The bill, introduced last December, already has149...