Yet he has vowed to stay in the race, counting on his loyal and impassioned followers to carry him into a position of influence at the Republican convention, if not to an upset victory.
"We're not one of the summer patriots," said Shawn House, carrying a gigantic inflated soft pretzel over his head. The pretzel bore the company name - Hempzel's - and the rallying cry "Free the Seed."
"Dr. Paul still has a chance," House said. "Romney doesn't have it locked up."
House, 48, of Lancaster County, said one of the many reasons he was voting for Paul was the candidate's position on hemp. Paul sponsored House Resolution 1831, which would amend the Controlled Substances Act to exclude industrial hemp from the definition of marijuana.
If it were to pass, House, who manufactures pretzels containing hemp seeds because of their health benefits (they are high in Omega-3 fatty acids) would no longer have to import the product from Canada.
"It's just common sense," he said. "Like a lot of what he stands for."
Many in the overwhelmingly white crowd, about three-quarters of them men who appeared to be in their late teens through early 40s, had come from hours away - Wilkes- Barre and Scranton and Lancaster and Paterson, N.J. Others were from suburban communities such as King of Prussia and West Chester. Finding any from Philadelphia was difficult.
Tara Schuster, 29, a cosmetologist from Scranton, said she had voted for Barack Obama in the last election but had switched to Paul's camp. "I'm supporting him because he follows the Constitution," she said. Asked to explain, she said, "I go with what my husband tells me."
Her husband, Tom, 31, a member of a therapeutic support staff who works with autistic children, said Paul had won his political allegiance "because he's for the Second Amendment and the First Amendment, he has sound money policies. and noninterventionist foreign policies."
Nearby, Chris Olson, 21, a film student at the Art Institute of Philadelphia, held a sign that read: "Freedom is the right of all sentient beings," a quote from Optimus Prime, a gladiator character in the Transformers movies and comic books. Olson began listing the numerous aspects of Paul's platform he embraced. "He wants to end the Fed, instate sound monetary policy so our economy can recover, we need to bring our troops back. Man, I could go on for hours. We're occupying other countries, and it's causing conflict."
His words were drowned out by the crowd chanting, "President Paul! President Paul!"
Several supporters seemed more in tune with Paul's general beliefs than policy specifics. "I don't advocate his drug policies," Sean Kennedy said.
But Kennedy, 30, who manages a fun center with bowling and go-carts in Warminster, said he didn't know exactly what those policies were and asked a friend to help him explain.
"He wants it to be more of a state issue," the friend said.
"Right," said Kennedy.
Ibn Abdul Khaaiq, 28, a developer from King of Prussia, one of the few African Americans at the rally, said Paul had been unfairly portrayed as racist. He blamed television primarily, he said.
"The media is trying to stop his popularity," he said, "because it is controlled by the military industrial complex."
Paul was scheduled to attend a fund-raising dinner Sunday night at the Marriott Hotel downtown, according to his campaign website. The $400 tickets were sold out.
Contact Melissa Dribben at 215-854-2590 or firstname.lastname@example.org .