Short answer: no. Long answer: No, but he can seize control of the party apparatus and decide the policy planks.
Of course, has been from the outset the main goal of Paul's presidential campaign. The worst the Paul people could do is bring the convention to a screeching halt Chicago '68-style. There's not a chance in the world that the powers that be within the Republican party, not to mention the vast majority of the Republican base, would EVER let Paul be nominated, and certainly not in such an underhanded and undemocratic way.
