\documentclass{article}
\begin{document}
   \tableofcontents
   \section[Short 1]{Long 1}
      \subsection[Sub1]{Subsection 1}
          \subsubsection[Subsub1]{Subsubsection 1}
   \section[Short 2]{Long 2}
      \subsection[Sub2]{Subsection 2}
         \subsubsection[Subsub2]{Subsubsection 2}
   \section[Short 3]{Long 3}
      \subsection[Sub3]{Subsection 3}
      \subsubsection[Subsub3]{Subsubsection 3}

\end{document}
