This week, the Conservative government introduced legislation which would create a vast system of warrantless Internet surveillance. Civil libertarians howled in protest.

Public Safety Minister Vic Toews told them they could either support the government's plan or side "with the child pornographers."

Many more people howled, including conservative newspaper columnists. A few Conservative MPs even dared to suggest that maybe the legislation wasn't entirely perfect and righteous in every way.

By the end of the week, Toews suggested that perhaps it might be possible to modestly amend the bill in unspecified ways - without aiding and abetting child pornographers.

As farce, this was amusing. As governance, it was appalling. But as an illustration of the thinking of the prime minister and his circle, it was invaluable.

There's always been a riddle at the core of Stephen Harper's party. They say they're for "small government" and "individual liberty." They say they oppose the "nanny state" and can't stomach "social engineering."

This libertarian streak has occasionally been expressed in policy.

A classic example is the gun registry. The Conservatives insisted it's simply wrong to force otherwise law-abiding gun owners to divulge private information about private property.

The gun registry has to go, they said. And it will. Legislation abolishing it passed the House of Commons this week.

A starker example is the long-form census.

Unlike the gun registry, there was almost no popular opposition to the long-form census. But that didn't matter to the prime minister. Without warning or discussion, he announced that the long-form census would be scrapped.

It was a matter of the highest principle, the government insisted. Citizens shouldn't be forced to divulge private information under penalty of law. (Critics noted that the short-form census, the agriculture survey, and others were also compulsory and would remain so. The government ignored the point.)

So far, so very libertarian. But note the other side of the ledger.

In September, the prime minister casually mentioned that he would restore emergency anti-terrorism powers that allowed judges to compel witnesses to testify in secret hearings and police to jail suspects without warrant for up to three days. These powers had been created after 9/11 but had been allowed to lapse in 2007 because they had never been used.

No matter, Stephen Harper said. They were essential. So he would restore them. And make them permanent.

Then there's FINTRAC (the Financial Transactions Reports Analysis Centre of Canada). Few Canadians know that banks, credit unions, casinos, race tracks, and other institutions that handle money are compelled by law to report vaguely defined "suspicious transactions" to a spy agency called FINTRAC and not tell their customers.

A few years ago, the federal privacy commissioner criticized FINTRAC for having "more personal information in its database than it needs, uses or has the legislative authority to receive." A random sampling of FINTRAC's files turned up some shocking examples of abuse.

But the Conservatives have never criticized or curtailed this "giant system of snitches Stalin would be proud of," as Alan Gold, past president of the Criminal Lawyers Association once called it. In fact, they expanded it.

Of course, in principle, there's nothing wrong with coming down on different sides of the civil liberties fence on different issues. Each situation must be judged on its own merits.

But anyone who sincerely believes in civil liberties will set a consistently high bar. Is this particular intrusion really necessary? Is it effective? Can we achieve our goal with less intrusive means?

As we saw with the long-form census, Stephen Harper's bar is sometimes set up in the clouds. Practical concerns are irrelevant. All that matters is the principle at stake, and it must never be violated even in the slightest.

Other times, the prime minister's bar is flat on the ground. It doesn't matter that law enforcement has done just fine without those emergency anti-terrorism provisions. It doesn't matter that there's reason to think they won't be able to keep doing so in the future. There is at least a hypothetical possibility that maybe these violations of basic civil liberties will be useful to some degree some day. And that's good enough for the prime minister.

Same with warrantless Internet snooping. The government has been unable to come up with a single instance where law enforcement couldn't do its job under the existing law. "You can't hide your crimes," a police officer warned child pornographers after a recent bust. "You can't hide your identities." And yet the government still insists that a vast new system of warrantless Internet spying is necessary.

One moment Stephen Harper is Ayn Rand. The next he's J. Edgar Hoover.

So how can we explain this? The prime minister could be suffering from some sort of personality disorder. But unless and until there's a diagnosis we'll have to go with something else.

It is this: Stephen Harper is interested in advancing certain political goals. Sometimes, a strong civil libertarian position helps do that. The long-form census, for example, generates the data that support social housing, employment equity, and other programs the prime minister doesn't like. Taking the Randian position was a way of undermining those programs indirectly, and looking principled doing it.

But sometimes civil liberties get in the way of doing what the prime minister wants to do. So he goes all Hoover.

The one constant is that civil liberty is not Stephen Harper's concern. It is merely something to be used or discarded as needed.