Sen. Rand Paul (R-Ky.) told the Conservative Political Action Conference this afternoon that the worst part about President Obama’s executive actions that “run roughshod over our rights” is the “precedent that it sets for lawlessness that may follow.”

“It isn’t just the harm this president is causing; it’s the future harm he allows by destroying checks and balances,” Paul said.

The potential 2016 candidate drew an overflow crowd and got the largest ovation so far at CPAC. Paul fans wore red “Stand with Rand” T-shirts and a pile of signs sat outside the ballroom for the attendees to wield.

Reminding the crowd of his filibuster over drones and his lawsuit against Obama for NSA surveillance, Paul asked the conservatives to imagine a time “when liberty is spread again from coast to coast” and “liberty is governed again by the Constitution.”

“You might think I’m talking about electing Republicans,” the senator said. “I’m not. I’m talking about electing lovers of liberty.”

It’s not good enough, he said, “to pick the lesser of two evils.”

“There’s a great and tumultuous battle underway, not of the Republican Party but of the whole country… Will you, America’s next generation of liberty lovers, will you stand and be heard?”

Paul’s speech focused largely on the Fourth Amendment.

“We will not trade our liberty for security — not now, not ever,” he said. “The NSA monitors your every phone call. If you have a cell phone, you are under surveillance. I believe what you do on your cell phone is none of our damn business. I believe this is a profound constitutional question.”

“There’s a great battle going on for the heart and soul of America and conservatives cannot forget this.”

Paul mused about the legacy of Obama, stressing that “a great president would have protected us from the prying eyes of the NSA.”

“I don’t question Obama’s motives, but history will remember his timid defense of liberty,” he said.