Of today's two big stories abroad--the Syrian assassinations and the murder of Israeli tourists in Bulgaria--the Syrian story got more attention. But it was events in Bulgaria that Trita Parsi had in mind when he wrote, in the Daily Beast, "All the ingredients of a repeat of the shots in Sarajevo in 1914 seem to be in place."

Parsi is guessing that Iran, as alleged by Israeli Prime Minister Netanyahu, is behind the terrorism in Bulgaria. He sees this as retaliation for the assassination of Iranian scientists that is widely attributed to Israel.

Certainly an earlier, failed act of terrorism had the hallmarks of Iranian retaliation. An attempt in India to kill the Israeli ambassador's wife employed the same technique used to kill Iranian scientists: a motorcyclist attached a bomb to a car. Now, says Parsi, "it appears that Tehran has shifted its focus to softer targets." He continues:

If this is the case, the ongoing dirty war between Israel and Iran may be getting out of control.

US officials have privately expressed concern that one of the purposes of Israeli attacks in Iran has been to generate an Iranian response that could serve as a casus belli for Israel. That way, Israel could target Iran's nuclear facilities without paying the heavy political cost of starting a preventive war.

It was partly for this reason that the US immediately and forcefully condemned the latest assassination of an Iranian scientist and denied any US involvement. Simultaneously, other major powers pressed Iran not to retaliate, arguing that Israel would use any retaliation to expand the war.

With the attack on the Bulgarian bus, the arrest of a Lebanese-Swedish man in Cyprus this week accused of planning attacks against Israeli civilians, and the US Navy's killing of an Indian fisherman whose boats got too close to the US ship in the Persian Gulf, the situation is clearly tense and all the ingredients of a repeat of the shots in Sarajevo in 1914 seem to be in place.

It's been a very hot summer, and absent some courageous and deliberate de-escalation, it may soon get much hotter.

Today's assassinations in Syria hastened the inevitable: the demise of the Assad regime. The terrorism in Bulgaria, in contrast, increased the chances of something that wasn't--and, we can hope, still isn't--inevitable.