TAMPA, Fla. — In a speech that was part motivational, part valedictory and at every opportunity critical of the mainstream Republican Party on the eve of its convention here this week, Representative Ron Paul declared his “liberty movement” alive and well on Sunday before a crowd of nearly 10,000 supporters who were eager to testify to that claim.

Mr. Paul said that he had recently read in newspapers that the so-called Ron Paul Revolution was over, and that whatever enthusiasm voters had shown toward his presidential campaign in the Republican primary season was gone.

“They only wish!” Mr. Paul thundered to an audience that seemed to become more energized with his every word, their roars of approval reaching a deafening level inside the Sun Dome at the University of South Florida.

On this evening, Mr. Paul, the longtime libertarian House member from Texas and presidential contender, was in characteristic form: animated, witty, irreverent and uncensored. He spoke for more than an hour to supporters who had waited five hours to hear him. At times, bursting with spirit, he shouted. At other moments, he lowered his voice to make his favorite points.