If it looks like an assassination and smells like an assassination, it probably is one
(or It's the Occam's Razor, Stupid!)

If you are interested in the current events in Lebanon, the NYTimes lengthy, above-the-fold story today on the deteriorating relationship between Bashar al-Assad and Rafiq Hariri before Hariri's assassination is a must-read.

On an unseasonably mild day last August, a small group of Prime Minister Rafik Hariri's closest political allies could tell from his flushed face and subdued manner that something awful had happened in the Syrian capital of Damascus, where he had been summoned to a meeting with President Bashar al-Assad.
...
After a few moments, he leaned forward and described how the Syrian leader had threatened him, curtly ordering him to amend Lebanon's Constitution to give President Émile Lahoud, the man Syria used to block Mr. Hariri's every move, another three years in office.

"Bashar told him, 'Lahoud is me,'" Mr. Jumblatt recalled in an interview. "Bashar told Hariri: 'If you and Chirac want me out of Lebanon, I will break Lebanon.'" He was referring to the French president, Jacques Chirac.

In the month since Mr. Hariri was assassinated, members of Lebanon's anti-Syrian opposition have pointed to that Aug. 26 encounter in Damascus as fateful. Although opposition leaders acknowledge that they lack firm evidence tying Syria or its Lebanese agents directly to Mr. Hariri's assassination, they link that day to his slaying on Feb. 14.
...
Syria is used to acting with impunity in Lebanon.

But by 2004, the Lebanese were expecting something different from Mr. Assad, not least because the United States had signaled by invading Iraq that business as usual was unacceptable.
...
The end for Mr. Hariri as prime minister came in October after the Syrians sent him a message to step aside. He resigned on Oct. 20, somewhat relieved, his aides said.

The next months were consumed mostly with planning for parliamentary elections due in the spring and wrangling over the election law. The Syrians were trying to gerrymander districts around Beirut and the rest of the country to weaken the opposition. But the Christian-Sunni Muslim-Druse coalition appeared to grow ever more formidable.

During this period, while he was planning his comeback, Mr. Hariri seemed to become his old self again, friends and allies said. Mr. Renaud, the European Union ambassador, recalls visiting him at his combined office and mansion right after Christmas and seeing him emerge from behind his desk waving a sheaf of papers and grinning, saying, "We are going to win the elections!"
...
By late January, Mr. Hariri was feeling confident enough that he decided he would not accept any Syrian-nominated members on his election list, his advisers say. His 19-member bloc in Parliament included three men chosen by Rustom Ghazale, the head of Syrian intelligence based in Anjar in the Bekaa region, and the man Lebanese believe really ran their country, his aides said.

Mr. Hariri invited Mr. Ghazale to lunch in late January and told him about the decision.

"They were not happy," said Ghazi Aridi, a former minister of information who resigned in September over the Lahoud extension. He recalls Mr. Ghazale telling Mr. Hariri, "You have to think about it and we have to think about it."

It was beginning to look like the opposition could capture about 60 seats in the 128-seat Parliament, enough to elect a president other than Mr. Lahoud. Around this time, Mr. Hariri and Mr. Jumblatt, the Druse leader, had a meeting. Mr. Hariri's earlier confidence that he would not be assassinated had slipped; the two men figured one or the other would be killed soon.

"Any field where you challenge them, they get mad," Mr. Jumblatt said. "Such totalitarian regimes cannot understand that you can have the freedom to chose your own M.P.'s, or you choose your own local administrators or I don't know what."

Two weeks after that conversation, the huge bomb that rocked all of Beirut struck Mr. Hariri's motorcade. He, along with 18 other people, died.
(emphasis mine)

Assassinations are not unheard of in the Middle East. Israel assassinated leaders of Hamas recently, as well as other members of the resistance. The difference one could argue, is that Hariri was resisting by peaceful means.