In a large saucepan combine crushed tomatoes, diced tomatoes, tomato sauce, minced garlic, sugar, parsley, garlic powder, salt, oregano, basil, and ground black pepper. Add capers and crushed red pepper if desired. Cover. Bring to a boil.
Lower heat and simmer, with cover, for 45 to 60 minutes.
As simmering time nears, in a large pot with boiling salted water cook spaghetti until al dente.