Signs and posters are among the rather lengthy list of items not allowed at President Barack Obama's rally on Library Mall Tuesday, which is sponsored by the Democratic National Committee.

This bothered local marijuana activist and 2012 U.S. Senate candidate Ben Masel, who said it infringes on his right to speak freely in a public space.

"How can a private body decide who gets to speak in a public forum?" he asked.

It's not a security issue. The Secret Service does not prohibit signs, just poles and sticks attached to the sign, said John Hirt, resident agent in charge of Secret Service for Wisconsin.

"The 'no sign' rule is being enforced by the DNC," Hirt said.

The Democratic National Committee is renting the space from the university at a cost of $10,000. A spokesman for the DNC said signs are not permitted so that the "experience is a positive one" for all attendees.

The city of Madison designated the 600 block of State Street as a peaceful assembly area. Masel said he will use that area if he can't get any closer to the rally.

He said he intends to bring a 3-foot by 2-foot foam core that reads, "HEMP IS JOBS."