Blood diamond: is writing petition enough?

Previously, it was mentioned on the article that Blood Diamond is a massive human trafficking by the Zimbabwean regime. On the same article, the recommendation from Human Rights Watch representative to fight against human trafficking by the regime was also mentioned. One of the recommendation is  that  American public is encouraged to write petition and letters to their elected officers to stop the atrocity committed by the Zimbabwe's president, Mugabe along with the recommendation to exercise discretion in purchasing the diamonds to ensure not buying Zimbabwean diamonds.