Dr. Norm Heimgartner looks at two operas performed by the Tacoma Opera on March 11 and 13. Trouble in Tahiti by Leonard Bernstein and Pagliacci by Ruggero Leoncavallo. Two marriages are in trouble. In Leoncavallo's famous work, passion, violence and revenge mingle to create the classic Italian opera. In Berstein's modern masterpiece, suburban discontent simmers to a distinctly American sound.