CHARLOTTE, N.C. - Political conventions mean big productions with big price tags. Among the largest expenses and headaches: security.

When the leader of the free world comes to town, one thing's for sure, it feels a little less free to move about.

"Whole city blocks are blocked off. You can hardly drive around town. If anything, I feel like we're contained in a green zone," Det Ansinn, from Doyletown, Pa., said.

Charlotte's invaders for the Democratic National Convention included not only delegates but thousands of security agents from around the country. The same proved true for Tampa, Fla., during the Republican National Convention.

The goal: protect America's politicians and their supporters.

"No, I'm not concerned about my safety," Kujenga Eliyah Ashe, from Columbus, Ohio, said. "Sometimes you need a large, sure force."

But sometimes the impression of a hospitable host city turns into something more like a police state.

Security in and around all the venues in Charlotte was tight. To get where you needed to go, you needed credentials.

But don't be fooled, even when you got there, there were more layers of security to go through.

"I feel very, very safe watching all these police officers and people with badges and the sheriff and everything else," Jackie Dozier, from Shreveport, La.

Whether you see miles and miles of barricades, security checkpoints, bomb-sniffing dogs, and law enforcement as a help or a hassle, one thing they also do is help run up a tab.

"Those are things you like not to think about," Ansinn said.

The host cities pick up a lot of the costs but Congress chips in some taxpayer money as well. Washington doled out $50 million to each convention for security, meaning taxpayers help foot the bill.

It's one of the few political events where it's a given that the most free and prosperous country in the world looks far from it.