Z:gnu-www-ja-copyright-and-globalization--3c668f-So the publishers are purchasi/en

So the publishers are purchasing laws to give themselves more power. In addition, they're also extending the length of time the copyright lasts. The U.S. Constitution says that copyright must last for a limited time, but the publishers want copyright to last forever. However, getting a constitutional amendment would be rather difficult, so they found an easier way that achieves the same result. Every 20 years they retroactively extend copyright by 20 years. So the result is, at any given time, copyright nominally lasts for a certain period and any given copyright will nominally expire some day. But that expiration will never be reached because every copyright will be extended by 20 years every 20 years; thus no work will ever go into the public domain again. This has been called &ldquo;perpetual copyright on the installment plan.&rdquo;