Sen. Rand Paul, R-Ky., electrified the audience at the Conservative Political Action Conference with a defense of civil liberties and an attack on what he argued was excessive surveillance by the National Security Agency.

Though most conservatives defended aggressive surveillance policies when President George W. Bush was in power, there has been a noticeable shift under President Obama, and now the base of the party is much more concerned about losing privacy in the name of defending national security.

The question is whether this will trend will reverse itself the next time a Republican is elected president.

Following Paul’s speech, I spoke with Matt Kibbe, president of the limited-government activist group FreedomWorks, about whether the momentum for a greater focus on civil liberties would be stopped if Republicans recaptured the White House.

“The younger people that are joining either the Republican Party or the conservative movement care about civil liberties a lot,” Kibbe argued. “And so it’s going to be hard to put the genie back in the bottle unless you want the party to die out.”

My view is that under a Republican president, criticism of any perceived overreaching on surveillance would be greater than it was under Bush, but not nearly as fierce as it is under Obama.

There have always been civil libertarians who have consistently criticized both Republican and Democratic administrations. But other conservatives are more partisan – or at the very minimum, more suspicious of Democratic presidents than Republican ones. And because much of this happens out of the public view, a lot of the issue ultimately comes down to trusting the president’s assurances that surveillance is done with privacy in mind, and to prevent terrorist attacks.

So, my guess is that many conservatives would be more willing to give the benefit of the doubt to a future Republican president. But the fact that civil libertarians have a figure like Paul to rally around means that the future Republican president would have to deal with more criticism from his or her own party than Bush, who was largely given a free pass on the right.

The wildcard in all of this is obviously whether there is another major terrorist attack. The more time that passes from Sept. 11, the less concerned Americans will become about terrorism and the more likely they’ll be opposed to aggressive surveillance. But another attack could change that calculus instantly.