Iraq dictator Saddam Hussein didn't have weapons of mass destruction, but two young Boston bombers did?

No doubt many Americans were a bit perplexed Monday when 19-year-old Dzhokhar Tsarnaev was federally charged with "using a weapon of mass destruction," even if the explosions at the Boston Marathon did result in three deaths and injuries to more than 170 people.

In the late 1990s, President Clinton and other top officials, in discussing the fears about the Iraq dictator, repeatedly used the term to describe chemical, biological and even nuclear weapons that could kill vast numbers in the Middle East.

The term grew to even greater currency with the Bush adminstration in the months before and after the invasion of Iraq in 2003. President Bush used the term four times in his 2003 State of the Union speech, warning that Hussein had the capability to produce enough anthrax and botulinum toxin to kill millions.

After the invasion, it became a point of much political discussion when no such "weapons of mass destruction" were found.

And the term's still being used that way. The new George W. Bush Presidential Library and Museum declares in one exhibit, "No stockpiles of W.M.D. were found," according to a piece published online Saturday by the New York Times.

And yet, of course, Hussein had lots of deadly bombs.

So Monday's charges seemed oddly worded to many ears.

It turns out the legal definition is extremely broad.

Indeed, it's broad enough to include whatever grenades or pipe bombs Tsarnaev and his older brother allegedly tossed toward police while trying to escape overnight Thursday.

According to a federal statute, "18 USC 2332a - Use of weapons of mass destruction," the term refers to four things.

Three do correspond to the concerns about Saddam Hussein:

"(B) any weapon that is designed or intended to cause death or serious bodily injury through the release, dissemination, or impact of toxic or poisonous chemicals, or their precursors; (C) any weapon involving a biological agent, toxin, or vector (as those terms are defined in section 178 of this title); or (D) any weapon that is designed to release radiation or radioactivity at a level dangerous to human life."

But category (A) is quite a catch-all, referring to "any destructive device as defined in section 921 of this title."

There, the term "destructive device" is defined as:

"(A) any explosive, incendiary, or poison gas - (i) bomb, (ii) grenade, (iii) rocket having a propellant charge of more than four ounces, (iv) missile having an explosive or incendiary charge of more than one-quarter ounce, (v) mine, or (vi) device similar to any of the devices described in the preceding clauses."

The section goes on to exclude devices not intended to be used as weapons, as well as rifles used for "sporting, recreational or cultural purposes."

With a broad definition like that, prosecutors seem to be on solid legal ground in describing those shrapnel-loaded Boston bombs as "weapons of mass destruction."

Contact staff writer Peter Mucha at 215-854-4342 or pmucha@phillynews.com.