However, censorship can be practised in covert ways. One of the
earliest attempts to restrict publication was the use of
deliberate taxation to inhibit circulation. A Stamp Tax
introduced in England in 1712 (and not removed until 1855)
required newspapers to affix stamps so that by raising the price
of stamps newspaper prices could be raised beyond the purchasing
power of all but wealthy readers. Censorship can also be
practised through harassment and intimidation. During the
"McCarthy era" in the US, the American Supreme Court, in US v
Rumely, warned, "Through the harassment of hearings,
investigations, reports, and subpoenas, government will hold a
club over speech and over the press." Censorship can also be
exercised through the pressure of advertisers and decisions by
newspapers themselves, particularly in circumstances where no
competitive or alternative source of news is available. In
Canada, the concentration of media ownership caused the Royal
Commission on Newspapers (1980) to caution that the key pr