The suicide of Interior Minister Ghazi Kanaan is a sign of the steadily growing pressure on the Syrian government. Mr. Kanaan's death eliminates a central figure in the investigation into the assassination of former Lebanese Prime Minister Rafik al-Hariri, but it will not end the inquiry, nor is it likely to help Damascus. Syria's isolation is increasing. It is unclear how the government of President Bashar Assad will cope with this pressure.

Mr. Kanaan was at the heart of Syria's intelligence and security apparatus. He spent 20 years in Lebanon, where he served as the head of Syria's military intelligence service. He was the ultimate power broker in Lebanon, with final approval of every important government appointment. His personal and political connections, and his efficiency, won him the interior ministry portfolio last year after a string of high-profile and unexplained killings in Syria.

This history, and his experience in Syria, made him a key figure when United Nations investigators began looking into the murder of Mr. Hariri, who was killed in a massive car explosion in Beirut on Feb. 14. The blast followed Mr. Hariri's efforts to eliminate Syrian influence in Lebanon; Damascus had virtually run the country for decades and used Lebanon as both a buffer between itself and Israel and as a staging ground for attacks by anti-Israeli proxies, such as Hezbollah, to help pressure Israel into returning the Golan Heights, seized in the 1967 war.