The bacteria are noticed only when troublesome, but researchers now believe that in normal times they perform many protective duties.
Sensitive to these complaints, the Canadian government has long imposed protective duties on some Chinese exports, such as hot-rolled steel plate.
All around him were the steelworkers, pressing Mr. Bush to speed ahead with an investigation that could result in large, protective duties on steel from countries accused of "dumping" their products in the American market.
Gottfried von Haberler in The Theory of International Trade (1937) suggested that the best way to distinguish between revenue duties and protective duties (disregarding the motives of the legislators) is to compare their effects on domestic versus foreign producers.
The government of Otto von Bismarck, German chancellor in the late 19th century, implemented protective duties on foodstuffs and manufactured goods (but kept free the importation of raw materials for use in industry).
In 1845, when the combination of the Irish famine and the arguments of Richard Cobden convinced Peel to repeal the protective duties on foreign imported grain known as the Corn Laws, Disraeli found his issue.
On the controversial issue of the Corn Laws, to which the landed interest in his party was very sensitive, he brought forward as one of his first measures a new bill drastically reducing the scale of protective duties.
Mr Bush hopes to use the investigation, which is likely to result in protective duties, as a sop to organised labour to help his push in Congress for trade-promotion authority, the speeded-up negotiating powers once known as fast-track.For this reason, Mr Bush's cabinet has been looking into the possibility of an investigation for months.
