Prepare for more domestic spying.

In the National Intelligence Estimate titled "The Terrorist Threat to the Homeland," which was released Tuesday, there's an intriguing section that suggests an impending push for more domestic surveillance.

Most of the report (which I analyzed here) concerns an alleged resurgence of al-Qaida. But toward the end, the authors mention a small but expanding number of "violent Islamic extremists inside the United States" who are "becoming more connected ideologically, virtually, and/or in a physical sense to the global extremist movement."

The report also notes dangers posed by "non-Muslim terrorist groups," "single-issue groups," and "even small numbers of alienated people" who might "find and connect with one another, justify and intensify their anger, and mobilize resources to attack—all without requiring a centralized terrorist organization, training camp, or leader."

Then comes the point:           

The ability to detect broader and more diverse terrorist plotting in this environment will challenge current U.S. defensive efforts and the tools we use to detect and disrupt plots. It will also require greater understanding of how suspect activities at the local level relate to strategic threat information and how best to identify indicators of terrorist activity in the midst of legitimate interactions.

One aspect of this is uncontroversial—the need to integrate city and state law enforcement ("suspect activities at the local level") to national watch lists and other databases ("strategic threat information"). This effort falls under the Department of Homeland Security, and it's a disgrace that, with such a large budget, nobody has yet devised a systematic method of doing this.

However, the other part of this passage ("how best to identify indicators of terrorist activity in the midst of legitimate interactions") pushes a very hot button.

A year and a half ago, passionate arguments broke out over reports about the National Security Agency's "data-mining" technologies. A couple of years earlier, the Pentagon attempted to fund a still-more intrusive program called the "Total Information Awareness" network. (The latter effort failed, but the concept was almost certainly re-routed to the NSA or elsewhere.) Concerns were raised about privacy rights, the abuse of power, and the worth of such networks to begin with.

Judging from the NIE (not just from these key passages but from its general assessment of a "persistent and evolving terrorist threat"), the debate over these vast surveillance systems will soon be renewed. So, it's worth making some distinctions that tended not to be made the last time around, at least in much of the public discussion.

The key distinction is the one between data-mining and wiretapping.