Where did the verb "to shanghai" come from?

Search: shanghai verb

Why: Page 133 of The Handmaid's Tale:

Their power had a flaw to it. They could be shanghaied in toilets.

Answer: The verb itself means:

1. To kidnap (a man) for compulsory service aboard a ship, especially after drugging him.
2. To induce or compel (someone) to do something, especially by fraud or force: We were shanghaied into buying worthless securities.

The most widely accepted theory of the word's origin is that it comes from the city of Shanghai, a common destination of the ships with abducted crews

It comes from American West Coast ports (Seattle, Portland, San Francisco, etc.) in the mid-1800s. Laws and economic conditions spurred conscripting men as sailors by forceful techniques such as trickery, intimidating, or violence.

1. Once a sailor signed onboard a vessel for a voyage, it was illegal for him to leave the ship before the voyage's end.
2. Crews abandoned ships en masse for the California Gold Rush, causing a shortage of skilled labor on the coast. Healthy, able seamen were rare and valuable.
3. Boarding masters (who found crews for ships) were paid "by the body," and thus had a strong incentive to put as many men on a ship as possible.
4. A kidnapping boarding master (or "crimp") might knock a seaman unconscious, forge his signature, and pick up his money.
5. A crimp might trick a sailor into using his advance pay (up to 4 months) to buy supplies and clothes from him for an inflated price.
   

Source: Wikipedia

The More You Know: The most infamous crimps included Jim "Shanghai" Kelly and Johnny "Shanghai Chicken" Devine of San Francisco, and Joseph "Bunco" Kelly of Portland. "Bunco" Kelly allegedly passed off a wooden Cigar store Indian as a much-needed crewman to a desperate ship's captain. Another romanticized story involves the "birthday party" Shanghai Kelly threw for himself, in order to attract enough victims to man 3 ships, including one named Reefer.