At the same time that the Bush administration attacks its critics for exaggerating the threat that anti-terrorism measures such as the PATRIOT Act pose to privacy and liberty, it validates one of the critics' main concerns: that legal exceptions made for certain special cases tend to be expanded.
The president himself, in his speech yesterday, defended the Justice Department's proposal for denying bail in terrorism cases by noting that bail already can be denied in certain drug cases. "The disparity in the law makes no sense," he said. "If dangerous drug dealers can be held without bail in this way, Congress should allow for the same treatment for accused terrorists."
Likewise, Bush defended the Justice Department's request to obtain private records through administrative subpoenas, without any need for approval from a judge or a grand jury, by noting that such subpoenas have been used in investigations of health care fraud. "If we can use these subpoenas to catch crooked doctors," he said, "the Congress should allow law enforcement officials to use them in catching terrorists."
I'm not sure about the bail proposal, but I think it's already too easy for the FBI to snoop through the records of innocent people. Whatever the merits of these proposals, defending them is much easier when you can cite precedent, whether or not the existing exceptions were justified to begin with. The rhetorical power of the status quo is one reason why organizations like the ACLU are reflexively suspicious of new law enforcement powers. Even if the proposal at hand is not so bad, it is apt to be cited in defense of worse things later on.
For more (a lot more) on the dynamics of slippery slopes, see Eugene Volokh's provocative analysis, published last fall in the Harvard Law Review. The debate over the PATRIOT Act and its possible sequels is a good opportunity to spot illustrations of the mechanisms he describes.